Minor League roundup, April 21: Keyner Martinez shows off

Ceballos, who has a .900 OPS and a 132 wRC+ on the year, is really putting his disappointing 2025 behind him, as the .670 OPS and the 102 wRC+ that he posted in AA last season looks more and more distant with every swing of the bat. It certainly seems that Ceballos has made a concerted effort to be more aggressive in the batter’s box. Last year, his passive approach drew him a lot of walks and kept his strikeout rate delightfully low, but it resulted in a lot of soft contact. As a result, he had just a .232 batting average and a lowly .106 isolated slugging, a disappointing mark after he had showed a lot of power in his debut stint with the organization in 2024, when he came over in the Jorge Soler trade.

This year, he’s bringing the aggression back, and swinging more. The result is that his strikeout rate has jumped (from 17.4% to 25.9%), but so has the average, which has leaped to .271, and the isolated slugging, which is all the way up at .250. After hitting just 6 home runs in 420 plate appearances with Richmond a year ago, Ceballos already has 3 in just 58 plate appearances this season.

All of that said … if you’re ever wondering why hitters who perform well in the Minor Leagues so often struggle in the Major Leagues, well … there are a lot of reasons, and one of them is the defense. It’s very hard to overstate just how bad Minor League defense is relative to what we watch on a daily basis in the big leagues. And as evidence, I present Ceballos’ “double”:

The other big star in the game was second baseman Diego Velasquez (No. 31 CPL), who had his best game of the young season, hitting 1-2 with a solo home run, a walk, a sacrifice fly, and a stolen base.

You’d imagine there’s a little frustration for the switch-hitting Velasquez, who first made it to AA in 2024, and is approaching 800 plate appearances at the level. He certainly hasn’t forced the issue, but you could make the case that his AA assignment is more about roster logistics than his personal development. He had a .677 OPS, a 107 wRC+, and just a 14.3% strikeout rate a year ago, with 19 stolen bases, and that’s someone who you could at least make a compelling argument for being in AAA, were second base not being occupied daily by Nate Furman (No. 39 CPL), whom the Giants certainly prefer at this juncture.

Velasquez’s numbers are quite similar this year to last year, though he has boosted the power a little, and has a .778 OPS and a 109 wRC+, with a 14.9% strikeout rate and 3 stolen bases in as many attempts (it tells you how the Eastern League is playing to start the year that Velasquez has increased his OPS by more than .100 points, but his wRC+ by just 2).

The questions remain for Velasquez — he’s lacking in physicality, lacking in power, and lacking in defensive value — though those are questions that also exist for Furman and Luis Arráez, so that doesn’t seem to be a huge issue for the Giants at the position. That said, it does feel telling that Velasquez wasn’t an NRI, and it seems like the 22-year old will be staying in Virginia for the foreseeable future.

Left fielder Scott Bandura also continued his hot play, hitting 2-5 with a double, a stolen base, and a strikeout, which saw his OPS rise to .905 and his wRC+ to 135. Most notably, Bandura has made a huge cut to his strikeout rate, which has dropped year-over-year from 26.3% in High-A/AA to just 16.2% in AA this year. His swinging strike rate has gone from 10.0% to 7.0%, as he is making more contact and better contact, though, again … Minor League defense, everybody:

A pretty uninteresting day on the mound, with RHP Logan Martin (the incoming piece in the Mason Black trade) making his 3rd start for the organization. Martin did some good things, most notably avoiding walking any batters. But on the whole it wasn’t a great showing, as he allowed 4 runs — including a home run — in just 4 innings, with 2 earned runs and 3 strikeouts. Despite the lack of walks, Martin threw just 45 of his 76 pitches for strikes. Martin has done a good job limiting hits this year, with just 9 allowed in 12.1 innings, but he’ll need to increase the strike-throwing. He has a 4.38 ERA and a 4.99 FIP on the season.

RHP Tyler Vogel had another scoreless outing, pitching the 9th inning with 1 hit and 1 walk allowed, plus 1 strikeout. Vogel, who has a very strong case to be made for being in AAA right now, retained his perfect 0.00 ERA, though he has walked 5 batters in just 7 innings. He’s only given up 5 hits though, and no extra-base knocks.

LHP Jack Choate (No. 37 CPL) didn’t have the best outing, as he ceded a home run, but he struck out 3 batters in 2.1 innings. It seems the Giants are moving forward with Choate as a reliever this year, and so far the result has been 16 strikeouts in just 10 innings, which is exciting for the funky southpaw.

High-A Eugene (12-4)

Eugene Emeralds beat the Hillsboro Hops (Diamondbacks) 5-3
Box score

The Ems used a pair of runs in the 8th inning to pull ahead against the Hops, and with that, succeeded in avoiding their first losing streak of the year. Keep that up, I say!

Those 2 runs came off the bat of right fielder Lisbel Diaz (No. 32 CPL), who smacked a go-ahead 2-run home run after Eugene had blown a lead in the bottom of the 7th. Way to save the day, Lisbel!

Diaz, who finished the day 1-4, started the season slow but now has 2 home runs in his last 3 games. That — and a tiny 11.6% strikeout rate — are the lone bright spots on the year for the 20-year old, who has just a .599 OPS and a 55 wRC+ through 10 games, with a .205 batting average and no walks drawn. But on Tuesday he was the hero, and really the only offensive player worth talking about, so here’s to more days worth writing about for the toolsy young outfielder.

The top prospects in Eugene all had a few nice moments, but altogether were uninteresting: center fielder Dakota Jordan (No. 5 CPL) hit 2-4 but struck out twice; shortstop Gavin Kilen (No. 7 CPL) hit just 1-5 with a strikeout; designated hitter Trevor Cohen (No. 15 CPL) hit 1-4 with a walk, a stolen base (his 10th!) and a strikeout; and left fielder Carlos Gutierrez (No. 18 CPL) went 1-4 with a double and a strikeout.

It was a really nice day on the mounding, starting with, well … the starter, LHP Charlie McDaniel. An undrafted free agent who debuted last year, McDaniel really struggled in 7 post-promotion starts with Eugene in 2025, posting a 5.77 ERA and a 4.82 FIP. But so far his 2026 is a case of learning and adapting, and Tuesday was the next data point, as he went 5 strong innings with just 2 hits, 1 walk, and 1 run allowed, while striking out 4. That was the 1st run that McDaniel had allowed all year (this was his 3rd start), and he needed just 61 pitches to get through 5 innings, throwing 41 of them for strikes.

McDaniel is remarkably consistent when it comes to throwing strikes. In Low-A last year, he walked 2.2 batters per 9 innings, then 2.4 in Eugene, and now 2.5 this year. His strikeouts per 9 innings, over those same 3 periods, went from 8.6 to 8.4 to 8.2. Consistency!

He’s a contact pitcher, and what he’s doing better this year is getting the ball back on the ground. He pitched well in San Jose in his debut season when he had a 46.8% ground ball rate, with just 0.3 home runs per 9 innings allowed. His struggles in Eugene last year included just a 33.3% ground ball rate, and 1.6 dingers per 9. This year? A 54.2% ground ball rate, and no home runs allowed yet.

RHP Ben Peterson closed out the game with a brilliant showing, striking out 2 batters while tossing 2 perfect innings. Like McDaniel, Peterson is an undrafted free agent who debuted last season and, like McDaniel, he wasn’t too sharp upon his Eugene debut following a 2025 promotion. In 27 innings last year, the UNC alum struck out 27 batters, while walking 12. But this year, the 24-year old already has 12 strikeouts in just 8 innings … and with only 1 free pass.

Low-A San Jose (12-4)

San Jose Giants beat the Ontario Tower Buzzers (Dodgers) 12-2

Another offensive explosion for the Baby Giants, who scored in double digits for the whopping 6th time already this season. Perhaps their big brothers in San Francisco could learn to do the same?

Yet despite the gaudy run total (again), the star for San Jose was on the mound, in the form of RHP Keyner Martinez (No. 10 CPL). We haven’t talked about Martinez all that much this year, but Tuesday’s start was one worth discussing, as the 21-year old was nothing short of dynamic.

Martinez, who was signed in 2023 out of Venezuela and enjoyed a serious breakout season a year ago, mowed down Ontario batters for 5 innings, giving up just 1 hit — a swinging bunt — and walking 1 batter, while striking out 7. That’s how you introduce a new team to the California League (this is the 1st season of affiliated ball for Ontario [California, not Canada], and the 1st game between the the Tower Buzzers and Baby Giants).

It was a tremendous display of strike-throwing prowess for Martinez, who did hit a batter, but otherwise threw 45 of 62 pitches for strikes. Martinez had a dominant showing in the ACL a year ago, and backed it up with a very nice run of games in a short stint with San Jose. But his 2025 got off to a slow start, as he allowed 7 runs in 6.2 innings through his 1st 2 starts. But it turns out that the 3rd time is, indeed, the charm. And now he looks much more like himself. And while the overall numbers are still poor — he has a 5.40 ERA and a 5.02 FIP — Martinez has 16 strikeouts against 5 walks in 11.2 innings, and those are exciting numbers.

RHP Jose T. Perez also pitched well, coming out of the bullpen to throw 2 scoreless innings with 1 hit, 1 walk, and 1 hit batter, plus 4 strikeouts. It’s been a fascinating career for the 22-year old Perez, who was signed in 2021 out of the Dominican Republic. He pitched just 3.1 innings that year, then lost the rest of the season to injury … and also 2022 ….. and 2023 ….. and 2024. He returned last year, made 1 appearance in the DSL, and then was the rare in-season international promotion, as he jumped up to the ACL. His numbers weren’t great in Arizona, but he still ended the season with a short stint in San Jose, where he begins this year, his 1st year of full-season ball.

Perez is struggling with command, as he’s walked 8 batters in 7.1 innings, but he’s also struck out 10, en route to a 6.14 ERA and a 7.58 FIP through 4 outings. Patience is certainly required, as this was just the 18th game of his young career.

The offense again put on a show, knocking 12 hits and drawing 9 walks. The star was first baseman Hayden Jatczak, an undrafted free agent from Kent State playing in his debut season. The right-handed hitter was an absolute force to be reckoned with, hitting 2-3 with a 3-run home run, drawing 2 walks, knocking in 4 runs, and striking out once. Hell of a day at the office!

Jatczak’s debut season has been a dream thus far, as he’s rocking a 1.019 OPS and a 161 wRC+ with a higher walk rate (22.9%) than strikeout rate (17.1%) through 15 games. The cold water for the UDFA is obvious, however: he’ll turn 25 later this season, and is nearly 3 years older than his average peer at the level. So we’ll need to see him face more advanced pitching before we start to mention him alongside Bo Davidson and Parks Harber as the next great undrafted hitter in the team’s system. But you can only beat up on the pitchers in front of you, and so far Jatczak is doing exactly that.

Also doing that is right fielder Cam Maldonado (No. 34 CPL) whose torrential attack on Cal League pitchers continues. Maldonado had just another brilliant day, hitting 3-4 with a double, a sacrifice fly, and a strikeout, while stealing 2 bases. It really does feel like July’s 7th-round pick found something, and saw it all click together. Following a subpar brief debut last year, look at what Maldonado has done to start his 1st full season:

First 9 games: 6-34, 0 home runs, 0 doubles
Next 5 games: 13-21, 6 home runs, 3 doubles

And just like that, the 22-year old has a 1.158 OPS and a 175 wRC+, and is putting himself on the radar.

Nice games for left fielder Damian Bravo and designated hitter Jeremiah Jenkins. Bravo, a 22-year old 15th-round pick in 2025, hit 2-4 with a double and a hit by pitch, raising his OPS to .780 and his wRC+ to 86; Jenkins, a 22-year old 14th-round pick in 2024, went 2-3 with a double, 2 walks, and a strikeout, boosting his OPS to 1.151 and his wRC+ to 182 in his 2nd pass through the level.

Speaking of “level,” it was the rare quiet day for shortstop Jhonny Level (No. 3 CPL) who hit just 1-5, though he didn’t strike out and he had an RBI. Level now has a 10-game hitting streak as he continues to look like a star in the making, even on his quiet days.

Home run tracker

3 — Sabin Ceballos — [AA]
2 — Lisbel Diaz — [High-A]
2 — Hayden Jatczak — [Low-A]
1 — Diego Velasquez — [AA]

Wednesday schedule

Sacramento: 6:35 p.m. PT vs. Albuquerque (SP: Carson Whisenhunt)
Richmond: 4:05 p.m. PT vs. Richmond (SP: Greg Farone)
Eugene: 6:05 p.m. PT at Hillsboro (SP: Tyler Switalski)
San Jose: 6:00 p.m. PT vs. Ontario (SP: Jordan Gottesman)