Diamondbacks Prospects of the Month (May)

Seth Beer, AFL Fall Stars Game, October 12, 2019 - photo credit rd_79 on Flickr

The first month of a long-awaited minor league season has passed, and here are the Diamondbacks prospects impressing me most at every level. The criteria: a legitimate case as the most valuable player on the squad while younger than league average age, and showing gains as a potential big leaguer.

Jorge Barrosa, CF
Low-A Visalia
Age: 20.4
2019 Highest Level: Low-A
ETA: 2024

Barrosa has more than done his job for the hard-luck Rawhide. Hitting lead-off most of the month (recently slotted two-hole) Barrosa’s had multiple hits in 10 of 20 games. The high-contact, hit-to-all-fields sparkplug achieved a .388 OBP while batting .314 with a 21.4 K% and 5.1 BB%. The strikeout rate is the highest of his short career and walk rate the lowest; I attribute this to a high volume of strikes and being more aggressive early in the count. I suspect these rates improve as we move along.

His listed 5’9″ 165 pounds may be generous, but he seems to know who he is at the plate, creating plenty of good contact like the following:



Seven of Barrosa’s 27 hits have gone for extra bases; six doubles and one yanked home run, but Barrosa is physically limited regarding slugging. His May .806 OPS has played just fine though. The doubles I’ve seen tend to look like the following, the ball staying in front of outfielders:



Barrosa also mans a fine center field although his arm might be fringy at best. He makes things happen on the basepaths as well, swiping six bags this month:


(He was fine)

Barrosa might be more quick than fast, but he’s proving advanced for his level, making a case for promotion. With further development, some room for physical growth and perhaps getting more selective at the plate, the young switch-hitter is chasing a big-league dream. The path isn’t as wide for Barrosa as some prospects but he makes the most of what he has, and it could be good enough.


Ryne Nelson, RHP
High-A Hillsboro
Age: 23.4
2019 Highest Level: High-A
ETA: 2022-2023

Nelson saved his best May start for last, throwing 6.2 scoreless with seven strikeouts and no walks against Tri-City (LAA) 5/26. (Unfortunately no broadcast.) In four May starts, Nelson’s gone 24 innings with a 2.45 ERA, 0.95 WHIP, 28 K, 8 BB.

The former Oregon reliever brings the intense closer’s fire to the mound, and a four-seam fastball sitting 94/95 with the propensity to tick up. Tyler Keenan got a healthy dose of one here:



The secondary offerings are key for Nelson’s transformation into starter. Nelson’s made big strides in the control department, but the quality of stuff and commanding the breaking ball(s) are still works in progress. Currently, Nelson is primarily a two-pitch guy pairing the big up-in-the-zone fastball with a classic looking, slower 12-6 curveball:



There used to be a more sweeping slider in there, but I haven’t seen it yet this season. Reports from instructs claimed the two breaking balls have differentiated themselves, but if I have seen it, it’s a subtle “slutter” getting offered to lefties. A changeup has been spotted which was not a big component of his 2019 arsenal. Here’s a look at the raw changeup, clocked at 83 mph:



Nelson is on a nice track from college reliever to professional starting pitcher with the big fastball leading the way. High-A seems like a fine place to polish the secondaries, but he’ll need to prove himself in the uppers before we slot him in the Diamondbacks’ future rotation. The fastball/curveball combo has Nelson on a path for at least a cup of coffee in a big-league bullpen.


Alek Thomas, CF/RF
Double-A Amarillo
Age: 21.2
2019 Highest Level: High-A
ETA: 2022-2023

With Corbin Carroll‘s season-ending shoulder surgery, the cloud around Kristian Robinson‘s legal and mental health issues, and Geraldo Perdomo‘s struggles, Thomas has become the headline hitter of the system. He hasn’t disappointed.

Thomas slashed .321/.407/.551 in May with 11 of his 25 hits going for extra bases. For an aggressive hitter like Thomas, the 19.8 K% and 13.2 BB% are particularly encouraging. Thomas has been yielding some center field time to others, but it’s not due to performance. Thomas is a rangy plus-defender. Speed on the basepaths hasn’t shown up in way of stolen bases, as he’s one for three attempts, but the lack of steals…well, when you hit yourself to second base, you don’t have to steal it.

Power potential has been the debate. Thomas puts everything he’s got into a lot of swings, so I’m not sure he’s gonna tap into more pop, but he did crush this fastball from J.P. France, which was one of two May home runs:



The opposite-field pop looks more like this triple against Josh Mitchell:



As much as I try not to compare players, it’s hard to not envision Adam Eaton-like production from Thomas. Thomas will get a chance to prove it in the bigs, maybe as soon as next year.


Seth Beer, 1B
Triple-A Reno
Age: 24.8
2019 Highest Level: Double-A
ETA: 2022



Beer is fun. What’s on top of those glasses?

Beer held his own his first month of triple-A. The Diamondbacks had a lot of call-ups and send downs this month, so although the numbers may not be eye-popping, he was a mainstay for the Aces. Hitting .277 with three home runs and a .866 OPS, Beer’s 16.8 K% suggests some gains made in a department that was never horrible. Here is a clutch blast against A.J. Puk on 5/14:


Good look at the swing:


Beer’s limited athletically, thus defensively, but the reports of being a dud at first base are incongruent with what I’ve seen. He committed one error this month, which I did not see, not because I wasn’t watching, but because the broadcast didn’t catch it on camera. Beer feels like a fine first baseman to me, it just puts more pressure on the bat to produce.

There’s the question of where he stands with the organization and how he fits in at the next level, so he may have to wait for the universal DH to get a chance, but I expect him to beat up on triple-A pitching until then.


Honorable mentions:

3B A.J. Vukovich, Visalia
1B Andy Yerzy, Visalia/Hillsboro
SP Ryan Weiss, Amarillo
SP Humberto Castellanos, Reno

Nate enjoys picking up the prospect scraps, turning over rocks to share what muddy treats he can find. Residing high up the Rocky Mountains with his wife and children, trying to stay cool, getting a broader view. A fan of the underappreciated, overlooked and disregarded. A true mud person trying to make informed mistakes.

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