Prospect Watch: Lonnie White Jr., Kelvin Diaz, Yojeiry Osoria

Our new Prospect Watch features daily updates on three players in the Pittsburgh Pirates’ system. Looking for the nightly game recaps? Check out Pirates Prospects Live:

Yesterday’s Results: Pirates Score Runs, Pummel Padres; Lonnie White, Jr., Gets Five Hits

Today’s Action: The Pirates Take Their Revived Offense to Blake Snell

WILBUR MILLER: Lonnie White Jr., OF, FCL Pirates (Rk)

The Pirates drafted Lonnie White, Jr., in the supplemental second round in 2021. He was a three-sport star in high school and had a scholarship to play baseball and football at Penn State. He’s a strongly built guy with plus speed and considerable power potential. He signed for $1.1M, nearly double the slot value.

After signing, White largely disappeared for nearly two years. He got into only nine games in 2021 and two in 2022, all in the Florida Complex League. There isn’t a lot of information about his injuries, but there were apparently elbow and hamstring problems. This year, he injured his thumb sliding in spring training and needed surgery. That kept him out until June 5.

When White returned, it was back in the FCL. After half a dozen games, he was batting 120/241/120, with 11 strikeouts in 25 ABs. Whether there were lingering effects from the surgery is hard to say, but since June 16 White has gotten hot. He’s 15-for-30 with four doubles and one home run. He’s walked four times and struck out only six. In his last 18 ABs, he struck out just once. One thing that seems to have helped is that he looks like he’s going with the pitch more, getting more hits to the opposite field, but that could simply indicate his swing has gotten more comfortable further out from the surgery. He’s a strong guy and doesn’t need to pull the ball to drive it.

White isn’t playing center field full time, probably because the Pirates have other players – Braylon Bishop and Jhonson Pena – who are getting time there. Of White’s 13 starts, six have been in center, six in right and one in left. He has more than enough speed to play center and, in limited observations, he seems to run good routes. His arm is at least average. White didn’t attempt a steal before this year, but so far he’s 5-for-5. Even if he was 0-for-5, it’s a good sign that the Pirates are OK with having him run.

Assuming he keeps hitting, the next big question for White will be when he moves up to Bradenton. The FCL Pirates have settled on White and Yordany De Los Santos batting 3-4 most days. The Marauders could have an impressive lineup if the two of them moved up and joined Termarr Johnson, Shalin Polanco, Enmanuel Terrero, Jack Brannigan, Rodolfo Nolasco and Nick Cimillo.

WILBUR MILLER: Kelvin Diaz, INF, FCL Pirates (Rk)

There’s going to be a bit of déja vu all over again here. The Pirates signed Jhonson Pena and Kelvin Diaz a couple weeks apart in 2019 and they’re very similar players. They’re both lean, wiry players who run well, make enough hard contact to have good gap power, and show a good eye at the plate.

Like Pena, Diaz didn’t play until 2021 due to the pandemic, and didn’t get a lot of playing time that year. He got just 52 ABs in the Dominican Summer League and didn’t hit much. He went back there in 2022 and played regularly, batting 218/388/368. He had very high walk and K rates, 18.8% and 23.5%, respectively. He didn’t hit for a good average, but he did show good gap power and enough speed to steal 17 bases in 22 tries. He played shortstop regularly and had issues with errors.

Also like Pena, Diaz is getting squeezed for playing time. While Pena has moved mostly to the outfield, Diaz is still playing infield, but he’s not going to play ahead of Yordany De Los Santos or Javier Rivas. He’s started only five games in the infield, two each at third and short and one at first. Diaz has done well at the plate in very limited playing time, just 25 plate appearances. He’s batted 278/480/389, with six walks and just two strikeouts. It’s encouraging that, so far, Diaz has shown some ability to drive the ball; in fact, a little over half his career hits have gone for extra bases. Hitters who get by at the low levels just by drawing walks don’t generally do well as they move up.

 JOHN DREKER: Yojeiry Osoria, LHP, DSL Pirates Gold

The Pirates signed a group of four pitching prospects that they were very high on during the 2019-20 international signing class. The group included Cristopher Cruz, the highest rated pitching prospect in the whole class by one source. It had Roelmy Garcia, who hit triple digits at 17 years old. It had Gilberto Alcala, who some with the Pirates liked the most out of the four pitchers. The fourth player was lefty Yojeiry Osoria, who received a $600,000 bonus. The group is all still around, but no one has stood out among them yet.

I saw a great scouting video of Osoria from about five months before he signed, and I was very impressed with how polished he looked. Things have not gone smoothly in his pro career so far. It started with the lost 2020 season, when he was supposed to debut. He then made ten starts in 2021, posting a 6.12 ERA and 16 walks in 25 innings. He also had ten wild pitches, so there were some clear control issues. They didn’t get any better in 2022, when he missed some time due to injury. In his six games, he walked 12 batters in 12.2 innings. He also had two hit batters and four wild pitches. The odd part is that he had command of his pitches before signing, something I’ve only heard three times in scouting reports when international players signed. I saw him hitting spots in his scouting video.

Things have changed so far in 2023 for the 20-year-old southpaw. Osoria has three scoreless appearances this season. He has four hits, three walks and 16 strikeouts in 12 innings. He’s throwing strikes again, which is a good sign. I saw a highlight video of his last outing, where he recorded a career high eight strikeouts. I noticed that every strikeout pitch was a breaking ball. It bears repeating that a lefty can get by at the lower levels basically by throwing strikes. I’ve seen lefties dominate at the lower levels with nothing other than control. If they make it to Double-A and have success, then you can finally believe the numbers. That’s unless you saw something else along the way, such as Anthony Solometo adding velocity this year.

If Osoria continues to throw strikes, then he should breeze through this level, especially if he’s doing it with off-speed pitches. When he signed back in 2019, the Pirates believed he would add velocity as he filled out his 6’1″ frame. That projection was key with signing him, because he was sitting 86-89 MPH at the time. He has filled out since signing, but I didn’t get to see the velocity in the video, with only one fastball among the 14 pitches I saw. He’s doing his work with a lot of off-speed stuff, which young hitters don’t see often from the left side. It’s best for now to remain cautious with the results, other than noting the improved control.

Prospect Watch Archives

6/25: Quinn Priester, Canaan Smith-Njigba, Jhonson Pena
6/24: Nick Gonzales, Jared Triolo, Adolfo Oviedo
6/23: Michael Kennedy, Po-Yu Chen, Wyatt Hendrie
6/22: Braxton Ashcraft, Jase Bowen, Maikol Escotto
6/21: Termarr Johnson, Connor Scott, Enmanuel Terrero
6/20: Cal Mitchell, Travis MacGregor, Alessandro Ercolani
6/19: Henry Davis, Bubba Chandler, Julian Bosnic

The Prospect Watch runs every day at noon, featuring three players from the Pittsburgh Pirates farm system.

Tim is the owner, producer, editor, and lead writer of He has been running Pirates Prospects since 2009, becoming the first new media reporter and outlet covering the Pirates at the MLB level in 2011 and 2012. His work can also be found in Baseball America, where he has been a contributor since 2014 and the Pirates' correspondent since 2019.

Having followed the Pirates fanatically since 1965, Wilbur Miller is one of the fast-dwindling number of fans who’ve actually seen good Pirate teams. He’s even seen Hall-of-Fame Pirates who didn’t get traded mid-career, if you can imagine such a thing. His first in-person game was a 5-4, 11-inning win at Forbes Field over Milwaukee (no, not that one). He’s been writing about the Pirates at various locations online for over 20 years. It has its frustrations, but it’s certainly more cathartic than writing legal stuff. Wilbur is retired and now lives in Bradenton with his wife and three temperamental cats.

John started working at Pirates Prospects in 2009, but his connection to the Pittsburgh Pirates started exactly 100 years earlier when Dots Miller debuted for the 1909 World Series champions. John was born in Kearny, NJ, two blocks from the house where Dots Miller grew up. From that hometown hero connection came a love of Pirates history, as well as the sport of baseball.

When he didn't make it as a lefty pitcher with an 80+ MPH fastball and a slider that needed work, John turned to covering the game, eventually focusing in on the prospects side, where his interest was pushed by the big league team being below .500 for so long. John has covered the minors in some form since the 2002 season, and leads the draft and international coverage on Pirates Prospects. He writes daily on Pittsburgh Baseball History, when he's not covering the entire system daily throughout the entire year on Pirates Prospects.

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