Why Wait? One Prospect Each MLB Team Must Call Up Now

With the trade deadline passed and August waiver trades no longer an option, the next surefire MLB shakeup will come when rosters expand in September.

That's when we'll get a chance to see some of the game's top prospects make their big league debuts, whether it's a contender looking for a spark or a rebuilding team assessing their in-house talent while looking ahead to next year.

But why wait until September to promote a guy who's ready now?

The obvious answer is that teams don't want to start a player's service time clock any sooner than they need to, especially in the case of those aforementioned rebuilding teams.

However, we've decided to throw caution to the wind and highlight one prospect that each MLB team should promote immediately.

            

To be eligible for inclusion, a player must not have passed rookie-eligibility limits (130 AB, 50 IP, 45 days on the active roster prior to Sept. 1).  

Baltimore Orioles: RHP Hunter Harvey

It's been a long journey for Hunter Harvey since he entered the 2015 season as the No. 68 prospect in baseball.

Injuries limited him to just 63.2 innings in the four years leading up to the 2019 campaign, and he's still working his way back to his pre-injury form. His 5.27 ERA in 71.2 innings between Double-A and Triple-A doesn't look great, but he's thrown the ball much better since moving to the bullpen.

In 11 relief appearances since the middle of June, he has a 3.48 ERA and a .167 BAA in 20.2 innings. He's already on the 40-man roster and will turn 25 in December, so it's time to see what he can do.

      

Boston Red Sox: RHP Trevor Kelley

The Red Sox are somewhat thin on "top prospects" right now with a crop of minor league talent that claimed the No. 30 spot in Bleacher Report's most recent farm system rankings.

Right-hander Trevor Kelley won't find his name on any top prospect lists, and he doesn't have overpowering stuff, but the results are tough to ignore. In 40 appearances at Triple-A Pawtucket, he has a 1.38 ERA and 0.98 WHIP with eight saves in 52 innings.

The 25-year-old is on the verge of making good as a 36th-round pick in 2015.

     

New York Yankees: RHP Deivi Garcia

The Yankees have a deep farm system, ranked No. 20 in our latest update, but most of their top-tier talent resides in the lower levels of the minors.

However, their No. 1 prospect, Deivi Garcia, has reached Triple-A this season at the age of 20 after opening the year at High-A.

The undersized 5'9" right-hander has electric stuff, and even if he doesn't immediately occupy a spot in the rotation, he's capable of being a dangerous weapon out of the bullpen with 142 strikeouts in 94.1 innings this year.

      

Tampa Bay Rays: RHP Jose De Leon

Jose De Leon was once regarded as one of the top pitching prospects in baseball, checking in at No. 23 in 2016 and No. 29 in 2017 among the league's top 100 prospects.

Forearm and lat strains cost him significant time in 2017, and he missed all of 2018 recovering from Tommy John surgery. Now 26 years old, his prospect star has faded, but he's finally back to 100 percent.

With a polished three-pitch mix that includes an excellent changeup, he's posted a 3.48 ERA with 59 strikeouts in 44 innings. He's already on the 40-man roster, and he's ready to help the big league staff.

     

Toronto Blue Jays: LHP Anthony Kay

One of the prospects acquired from the New York Mets in the Marcus Stroman trade, left-hander Anthony Kay is enjoying a breakout season in the upper levels of the minors.

Signed below-slot as the No. 31 overall pick in the 2016 draft, he needed Tommy John surgery at the onset of his professional career. He finally made his pro debut last year and immediately showed the same polished three-pitch mix he featured at UConn.

Since he'll need to be added to the 40-man roster this offseason to be protected from the Rule 5 draft, the rebuilding Blue Jays have every reason to give him a late-season audition with an eye on a 2020 rotation spot.

Chicago White Sox: IF Danny Mendick

The White Sox opted against calling up uber-prospect Eloy Jimenez last year, and there's no reason to think they'll treat things any differently with Luis Robert. He's clearly ready, but he'll likely have to wait until next season.

Instead, the pick here is versatile infielder Danny Mendick, who has quietly put together a strong season in Triple-A after beginning the year well off the prospect radar.

A 22nd-round pick in 2015, he's hitting .278/.371/.445 with 21 doubles, 14 home runs and 18 steals, and he's capable of playing second base, shortstop, third base and left field. His ceiling might be a super-utility role, but he's ready to contribute now.

        

Cleveland Indians: RHP James Karinchak

A few weeks ago, outfielder Daniel Johnson would have been the obvious choice here. However, after Franmil Reyes and Yasiel Puig were acquired in the Trevor Bauer trade, he no longer has a clear path to playing time in the big league outfield.

Left-hander Logan Allen was also part of the Bauer trade. He's MLB-ready, but there's not currently a spot for him in the rotation, and his stuff won't necessarily play up out of the bullpen.

That brings us to reliever James Karinchak, who has used a 70-grade fastball and a hammer curveball to rack up an absurd 49 strikeouts in 19.1 innings over three levels. The Indians bullpen has been solid, but you can never have too many arms.

     

Detroit Tigers: SS Willi Castro

The Tigers have nothing remotely resembling a long-term answer at the shortstop position on the MLB roster. However, they may have found a solution at the 2018 trade deadline when Willi Castro was acquired from the Indians in exchange for outfielder Leonys Martin. 

The 22-year-old is hitting .294/.366/.426 with 34 extra-base hits and 17 steals at Triple-A, and MLB.com noted that he has the "soft hands, actions and arm strength to stick at shortstop," so the defensive profile is there too.

Giving him an extended look now could keep the Tigers from needing to sign another Jordy Mercer-type stopgap during the upcoming offseason.

     

Kansas City Royals: 3B Kelvin Gutierrez

With nine rookies on the current 25-man roster, the Royals have already promoted much of their MLB-ready talent in the midst of a full-blown youth movement.

Meanwhile, most of the top prospects still residing in their No. 11-ranked farm system are still at least a year or two away from being MLB-ready.

Third baseman Kelvin Gutierrez saw 20 games of MLB action during the first half, hitting .260/.304/.356 with four extra-base hits in 79 plate appearances. He's a plus defender at the hot corner with a good hit tool and an advanced approach. At 24 years old, he has little left to prove in the minors.

     

Minnesota Twins: RHP Brusdar Graterol

"I would not be surprised to see him up in Minnesota at some point."

That's what Twins assistant general manager Rob Antony told SKOR North with regard to top pitching prospect Brusdar Graterol.

The 20-year-old posted a 1.89 ERA and a .188 BAA in nine starts at Double-A to begin the season before missing time with a shoulder issue. He's currently on a rehab assignment in rookie ball and could return to the upper levels of the minors soon.

After failing to add an impact starting pitcher at the trade deadline, Graterol could be in the in-house answer the Twins are looking for as they try to hold off the hard-charging Indians in the AL Central standings.

Houston Astros: OF Kyle Tucker

The Astros already have a stacked offense, and Kyle Tucker could make them even more dangerous down the stretch.

Veteran right fielder Josh Reddick is hitting just .208 with a .517 OPS since the All-Star break.

Meanwhile, Tucker has posted a .903 OPS with 23 doubles, 28 home runs and 81 RBI in 103 games at Triple-A this year. The 22-year-old fell flat in his first taste of MLB action last season, but he still has star potential, and he's earned another shot.

      

Los Angeles Angels: IF/OF Jose Rojas

A 36th-round pick in 2016, infielder Jose Rojas has already exceeded expectations by even entering the conversation for an MLB call-up.

He's done nothing but hit since beginning his pro career with a .296/.352/.504 line over parts of four minor league seasons, and he's hitting .307/.373/.600 with 35 doubles, 26 home runs and 90 RBI in 103 games at Triple-A.

The 26-year-old has seen time at first base, second base, third base and left field, and he's capable of carving out a spot as an offensive-minded utility player.

      

Oakland Athletics: C Sean Murphy

The catcher position has produced a .696 OPS for the Athletics this season, and with Josh Phegley landing on the disabled list with a thumb injury, they are left relying on Chris Herrmann and Dustin Garneau.

Meanwhile, top prospect Sean Murphy is back healthy after suffering a torn meniscus and raking at Triple-A with a .360/.434/.685 line and seven home runs in 23 games.

The 24-year-old has a rocket arm and plus receiving skills, and he's taken his offensive game to another level the past two years. He has all the makings of a franchise catcher and a perennial All-Star; it's just a matter of shaking the injury bug that has plagued him throughout his pro career.

     

Seattle Mariners: LHP Taylor Guilbeau

A lefty reliever with a mid-90s fastball and a nice slider, Taylor Guilbeau has the goods to be a solid contributor out of an MLB bullpen in the near future.

The Mariners acquired him from the Washington Nationals at the trade deadline in exchange for Roenis Elias, and he's turned in a pair of scoreless appearances at the Triple-A level since joining the Seattle system.

The 26-year-old posted a 1.74 ERA in 10.1 innings in the Arizona Fall League, and he's followed that up with a 2.76 ERA and a career-high 10.4 K/9 in 45.2 innings between Double-A and Triple-A this year. He's ready for a look, and the Seattle bullpen needs help.

      

Texas Rangers: LHP Brock Burke

To be honest, it's somewhat surprising that Brock Burke has not already made his MLB debut.

The 23-year-old was acquired during the offseason as part of the Jurickson Profar trade, and he's on the 40-man roster. He was slowed by a blister problem early in the season, but he's healthy now and has posted a 3.18 ERA and 1.02 WHIP with 49 strikeouts in 45.1 innings.

Meanwhile, the Rangers have used 14 different starting pitchers already this year. Burke was promoted from Double-A to Triple-A on Tuesday, which could be a precursor to a late-season debut in the big leagues.

Atlanta Braves: RHP Kyle Wright

Kyle Wright has been roughed up in four starts at the MLB level this season, posting a 9.72 ERA with 22 hits allowed and 13 walks in 16.2 innings.

However, he has been pitching extremely well of late at Triple-A with five straight quality starts.

The 23-year-old still has front-line starter upside if everything clicks, but for the time being, he could prove to be an asset in a multi-inning role out of an Atlanta bullpen that remains in a state of flux despite the deadline additions of Shane Greene and Chris Martin.

      

Miami Marlins: RHP Jorge Guzman

Flame-throwing Jorge Guzman has dealt with some command issues this season at Double-A, walking 60 batters in 115.2 innings while posting a 1.31 WHIP.

That said, he's been much better of late with a 3.12 ERA and .194 BAA in his last five starts, and his last time out, he threw seven scoreless innings of one-hit ball, walking just two while striking out seven.

The 23-year-old continues to work as a starter, but his future may yet be in the bullpen, where his 80-grade fastball that touches 103 mph and good slider would undoubtedly play up. While he has yet to play above the Double-A level, he's already on the 40-man roster, so a jump straight to the majors is not out of the question.

     

New York Mets: RHP Ryder Ryan

The Mets have a thin farm system, and top prospects like Ronny Mauricio, Andres Gimenez, Francisco Alvarez and 2019 draft picks Brett Baty and Matthew Allan are still several years from contributing at the highest level.

Digging a bit deeper into the system, right-hander Ryder Ryan is someone who could potentially help with the team's push for a wild-card spot.

Since the beginning of June, he has a 1.45 ERA and .188 BAA in 18.2 innings, and he has recorded more than four outs in each of his last seven appearances. He's currently pitching at Double-A and is not on the 40-man roster, but he'll need to be added this winter, and he has the stuff to handle an aggressive promotion to the majors.

      

Philadelphia Phillies: RHP Enyel De Los Santos

Enyel De Los Santos still needs to further refine his curveball as a viable third offering if he's going to make it as a starter in the majors.

That said, his lively mid-90s fastball and plus changeup is MLB-ready, and he's capable of helping out in the bullpen for a Phillies team that has seen a lot of turnover on the pitching staff this year.

The 23-year-old has a 7.36 ERA in five appearances at the MLB level so far this season. However, he's allowed just three hits and one unearned run in nine innings over his last two outings at Triple-A, and it could be time for another look.

      

Washington Nationals: 2B/SS Carter Kieboom

Besides homering in his MLB debut and going yard again two days later, Carter Kieboom had a forgettable 11-game stint in the majors earlier this year, going 5-for-39 (.128 BA) with 16 strikeouts.

The 21-year-old has annihilated Triple-A pitching all season, though, with a .312/.411/.525 line that includes 21 doubles, 15 home runs and 70 RBI in 401 plate appearances.

The Nationals recently signed Asdrubal Cabrera to provide some support for Brian Dozier at second base, but neither of those veterans will be around beyond this season, and both have produced below a league-average rate. Kieboom is the future at the position, and he could prove to be an immediate upgrade.

Chicago Cubs: LHP Danny Hultzen

Remember Danny Hultzen?

He was the No. 2 overall pick in the 2011 draft, sandwiched between UCLA teammates Gerrit Cole and Trevor Bauer, and also chosen ahead of Anthony Rendon (6), Francisco Lindor (8), Javier Baez (9) and George Springer (11).

He began the 2013 season as the No. 29 prospect in baseball after reaching Triple-A in his first full pro season, but injuries derailed his career from there, and he pitched just 54.1 innings over the next six seasons.

The 29-year-old is healthy once again and pitching at Triple-A Iowa where he has a 1.74 ERA with just three hits allowed and 16 strikeouts in 10.1 innings. What a story it would be if he could finally break through and make his MLB debut, and the Cubs bullpen could use some help.

     

Cincinnati Reds: RHP Jimmy Herget

At some point, the Reds need to give Jimmy Herget a chance to prove he belongs in the MLB bullpen.

The 25-year-old has a 2.94 ERA and 10.5 K/9 in 215 career minor league appearances, 117 of which have come at the Triple-A level. He was roughed up in three appearances in the majors earlier this year, but he deserves a longer look based on his stellar track record.

With a deceptive sidearm delivery and a good fastball-slider combination, he at the very least has the potential to develop into a Steve Cishek-type middle reliever.

     

Milwaukee Brewers: RHP Trey Supak

The Brewers desperately need starting pitching help.

Meanwhile, right-hander Trey Supak has posted a 2.28 ERA, 0.89 WHIP and .195 BAA in 134.1 innings between Double-A and Triple-A this year, and he's already on the 40-man roster.

The 23-year-old does not have overpowering stuff, as evidenced by his pedestrian 7.0 K/9 rate, but he has a polished four-pitch mix, plus command and a durable 6'5", 240-pound frame.

     

Pittsburgh Pirates: 3B Ke'Bryan Hayes

Third baseman Colin Moran has been a liability for the Pirates defensively this season (-9 DRS, -18.8 UZR/150) and his middling offensive production (98 OPS+, 30 XBH) has done little to offset that fact.

Top prospect Ke'Bryan Hayes is not lighting the world on fire at Triple-A with a .251/.332/.404 line and 35 extra-base hits in 85 games. Still, the 22-year-old is a standout defender with a 60-grade hit tool and 50-grade power. It's only a matter of time before everything clicks.

The Pirates front office is notorious for holding back prospects. Look no further than Austin Meadows thriving in Tampa Bay after not getting much of a chance in Pittsburgh. Perhaps they've seen the error of their ways and will give Hayes a shot down the stretch to show he's ready for the everyday third base job.

    

St. Louis Cardinals: OF Randy Arozarena

What more does Randy Arozarena need to do?

The 24-year-old climbed up prospect rankings with a breakout 2018 season and then hit .309/.422/.515 in 28 games at Double-A this year to earn a quick promotion to Triple-A. Since reaching the highest level of the minors he's been even better, raking to the tune of a .376/.446/.570 line that includes 16 doubles and six home runs in 48 games.

The Cardinals have been searching for an offensive spark all season, and even with an outfield logjam of sorts in the majors, Arozarena could provide just that if given the chance.

Arizona Diamondbacks: IF/OF Joshua Rojas

The D-backs acquired three top-tier prospects from the Astros in the Zack Greinke deal, with right-handers Corbin Martin and J.B. Bukauskas and slugger Seth Beer appearing on various leaguewide top 100 lists at one time or another.

However, it's the fourth prospect piece in the deal who could be the first to don a Diamondbacks uniform. A 26th-round pick in 2017, Joshua Rojas is hitting .329/.418/.594 with 31 doubles, six triples, 21 home runs and 33 steals in 101 games between Double-A and Triple-A.

The Diamondbacks have shown an affinity for guys that can play all over the field with Brandon Drury, Chris Owings and 2019 breakout star Ketel Marte all deployed in roving roles. Rojas is cut from a similar cloth.

      

Colorado Rockies: OF Sam Hilliard

At 25 years old and with a full season at the Triple-A level now under his belt, Sam Hilliard is a finished product.

He's going to strike out a decent amount and he might never hit .250 in the majors, but his power is legit, he runs well and he has the tools to be an above-average defensive right fielder.

He has an .863 OPS with 29 home runs and 20 steals this season, and if the Rockies are going to entertain the idea of trading Charlie Blackmon this winter, it might be a good idea to get a long look at Hilliard now as a potential replacement.

    

Los Angeles Dodgers: 2B/SS Gavin Lux

If there is any top prospect who is going to force his team's hand into an earlier-than-expected promotion, it's Gavin Lux.

The 21-year-old is hitting an absolutely ridiculous .452/.537/.841 with 27 extra-base hits in 30 games since being promoted to Triple-A, and he has slugged 22 home runs total this season after hitting just 22 total in his first three pro seasons.

With Max Muncy and Corey Seager manning the middle infield spots on an everyday basis at the MLB level, there's no clear path to playing time. But if Lux keeps hitting like this, the Dodgers will find a way to get his bat into the lineup.

     

San Diego Padres: 3B Ty France

Veteran Ian Kinsler was signed to serve as a stopgap while Luis Urias and Fernando Tatis Jr. settled in as the everyday middle infielders. He's hitting just .217 with a .636 OPS in 277 plate appearances on the season.

Meanwhile, Ty France is batting a robust .391/.472/.771 with 23 doubles and 26 home runs in 69 games at Triple-A, and it might be time to open up a spot for him on the MLB bench by designating Kinsler for assignment.

France, 25, is limited to the corner infield spots and he's not going to steal a starting job from Eric Hosmer or Manny Machado any time soon, but his right-handed power has value.

As MLB.com wrote, "Ultimately, his bat might prove too valuable to ignore."

     

San Francisco Giants: RHP Melvin Adon

Who doesn't love a good 102 mph fastball?

After spending the bulk of his career working as a starter, Melvin Adon pitched out of the bullpen in the Arizona Fall League last year and turned heads with a 2.92 ERA and 21 strikeouts in 12.1 innings.

The 25-year-old backs his electric fastball with a wipeout slider. He's used that combination to rack up 59 strikeouts in 46.1 innings between Double-A and Triple-A this year, saving 14 games along the way.

With a spot on the 40-man roster and a recent call-up to Triple-A, things are lining up for him to make his MLB debut in short order.

       

All stats courtesy of Baseball Reference and FanGraphs, unless otherwise noted.