Why Bryce Harper, Mike Trout Are Just Start of MLB's Next Wave of Call-Ups

Mike RosenbaumJun 5, 2018

With Bryce Harper and Mike Trout now regulars in the major leagues, it’s safe to say that the next wave of elite prospects has arrived. But as always, this begs the question: Who will be the next prospect to reach the majors?

Obviously, when there’s an injury, a prospect’s estimated time of arrival is bumped up due to the immediate need for similar production. A perfect example is Will Middlebrooks, who was called up by Bobby Valentine and the Boston Red Sox Wednesday to replace Kevin Youkilis at third base.

But there are also prospects who flat-out earn their opportunity to crack a major league lineup or rotation, as can be seen in Diamondbacks’ promotion of Pat Corbin to replace the struggling Josh Collmenter as the team’s No. 5 starter.

So, before another highly-touted prospect is recalled—which could be any minute at the current rate—here is insight into five players who may be the next ones to reach the big leagues.

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Nolan Arenado, 3B, Colorado Rockies

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Double-A: .299/.378/.423, 10 XBH, 14 RBI, 16 K/9 BB (27 G)

Let’s be real, the Colorado Rockies do not have a legitimate third baseman. Yes, Jordan Pacheco is hitting well in Triple-A, but he doesn't have the power associated with a major league third baseman.

However, they do have Arenado—Prospect Pipeline’s No. 21 prospect—who is batting .299/.378/.423 in Double-A after a phenomenal 2011 campaign (.298/.349/.487, 55 XBH, 122 RBI) at High-A. He hasn’t gone deep as frequently this season, but he’s still tallying plenty of doubles and the season is still young.

Although I believe spending the entire 2012 season in the minor leagues would be best for his development, there’s a chance that Arenado could be recalled much earlier than anticipated if he catches fire.

Trevor Bauer, RHP, Arizona Diamondbacks

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Double-A: 5-1, 34.1 IP, 2.36 ERA, 46 K/20 BB (6 GS)

The Diamondbacks have made it a point twice that they believe Bauer—Prospect Pipeline's No. 8 prospect—needs more refinement (particularly with his fastball command) at Double-A and possibly Triple-A before making his debut.

They cut the right-hander from big league camp, opting to go with Joe Saunders and Josh Collmenter instead, and just this week promoted left-hander Pat Corbin to the back end of the rotation.

Bauer has pitched well at Double-A to begin the season, but as Mike Newman at FanGraphs contends, they are erring on the side of caution with his development—and it’s admirable.

Heath Hembree, RHP, San Francisco Giants

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Triple-A: 11 IP, 7 SV, 1.64 ERA, 10 K/3 BB (11 G)

Brian Wilson’s season-ending injury opened the door for Heath Hembree, or so it seemed.

A 6’4” right-hander, Hembree has been excellent this season as the Triple-A Fresno closer. In his last five innings spanning five games, he has not allowed a hit while notching a save in each game.

But is it worth replacing Santiago Casilla, who has been excellent since inheriting the closer role? Probably not, but with Hembree pitching so well in Triple-A, the Giants will inevitably have to consider adding him to their bullpen.

Who knows, maybe they end up dealing Casilla for a bat and promote the big right-hander.

Shawn Tolleson, RHP, Los Angeles Dodgers

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Double-A: 10.2 IP, 4 SV, 0.84 ERA, 0.84 WHIP, 18 K/3 BB

Now in his second season at Double-A, Shawn Tolleson is on pace to post even gaudier numbers than he did in 2011.

The right-hander is one of the best swing-and-miss relievers in the minor leagues, and his track record suggests the potential to be a successful closer when finally given the opportunity. Perhaps what’s most impressive about his current season is that he’s inducing 2.67 ground balls per fly out.

With Javy Guerra struggling, Kenley Jansen is the next logical choice at closer for the Dodgers—and with good reason. But if there’s an injury or Jansen is ineffective, Tolleson could briefly stop at Triple-A on his ascent to the Dodgers bullpen.

Michael Taylor, OF, Oakland Athletics

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Triple-A: .347/.390/.547, 15 XBH, 18 RBI, 6 SB,

While the Oakland A's roster is loaded with outfielders, they continue to offer limited production—except for Yoenis Cespedes. Therefore, it wouldn’t surprise me if they recalled Michael Taylor from Triple-A in the near future.

It seems as though Taylor may have finally figured things out in his third straight season at Triple-A Sacramento.

At 6’5”, 255 pounds, he looks like a football player playing baseball. Taylor has the potential to hit both 20 home runs and doubles over a full season, and could even steal 10-plus bases. Now it’s just a matter of how much playing time he’ll ultimately receive.

UPDATE: The A’s have called up Taylor, placing Coco Crisp on the 15-day DL with an inner-ear infection.

Ryan Wheeler, 3B, Arizona Diamondbacks

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Triple-A: .315/.339/.537, 13 XBH, 23 RBI, 58 TB, 20 K/5 BB

Given Ryan Roberts’ slow start to the season and that Cody Ransom is currently spelling him, the Diamondbacks may be forced to explore other options at third base.

While they have plenty of talent on the farm to trade for a bat (if needed), they also have Ryan Wheeler, who is hitting well enough to warrant a look.

He’s a left-handed hitter with slightly above-average power potential who has moved a level each year through the system.

Over his last 10 games, Wheeler is batting .463 (19-for-41) with eight extra-base hits and 16 RBI. Perhaps a platoon with Roberts/Wheeler might be the best fit, as he’s batting only .174 (4-for-23) against left-handers this season. Either way, there will still be too many strikeouts coming from a bat-first position.