10 MLB Prospects Who Caught Our Attention In June
Image credit: Jared Sundstrom (Photo by Bill Mitchell)
Each month during the season, Baseball America publishes one organization report for all 30 clubs.
These reports by our major league correspondents contain a trove of player development updates and spotlight traditional reporting. Here are 10 updates I found to be especially enlightening from our June reports.
Top June Prospect Takeaways
1. Mariners prospects moving from High-Everett to Double-A Arkansas are bound to get whiplash. The former is a hitter’s haven, while the latter is one of the most brutal hitting environments in the minor leagues. Arkansas right fielder Jared Sundstrom is making the best of the situation, with an .842 OPS in road games and a .568 mark at home. But a closer look at the 23-year-old Sundstrom reveals an interesting tool set. “He’s a threat to steal and he’s a threat to hit the ball out of the park,” Mariners farm director Justin Toole said. “Any time you’re able to do both of those things, it’s a fun combination from a development standpoint.”
2. Six-foot-three Angels prospect Hayden Alvarez is growing into his body in the Arizona Complex League. The 18-year-old Dominican center fielder has already set a new bar for exit velocity while maintaining a strong hit tool. Alvarez is hitting .381/.475/.495 with 15 stolen bases through 31 games. “He’s always had a foundation for plate discipline and contact,” Angels assistant GM Joey Prebynski said, “and as he’s continued to get stronger and mature, we’re seeing the power and exit velocity tick up.”
3. Kyle DeBarge was a first-team All-America shortstop last year at Louisiana-Lafayette. This year, he is an intriguing prospect playing second base for High-A Cedar Rapids in the Twins’ system. The 21-year-old has unlocked his baserunning potential as a pro, stealing 37 bases in his first 38 tries, and now the Twins will focus on developing his bat. “We think he’ll have some sneaky pop along the way,” Twins GM Jeremy Zoll said. “He does a nice job controlling the zone, talking his walks. But with his bat speed, there’s definitely some sneaky pop in there.”
4. The Diamondbacks promoted 2024 first-rounder Slade Caldwell to High-A Hillsboro on June 10 after he batted .294/.460/.454 in 48 games for Low-A Visalia. What’s most notable about the rapid promotion is that Caldwell, taken 29th overall, is one of just two 2024 first-round high school picks to reach High-A. The other is shortstop Konnor Griffin, drafted ninth overall by the Pirates. As to Caldwell, he said: “I like getting on base a lot. I like seeing a lot of pitches, seeing what the pitcher has and not being uncomfortable in those two-strike counts.”
5. The Mets signed Division II Tampa righthander Anthony Nunez as an undrafted free agent about a year ago. The 23-year-old reliever quickly pitched his way to Double-A, but that’s not the most remarkable part. Until last year, Nunez was a switch-hitting third baseman. But once he got on the mound for the 2024 D-II champions, the die was cast. “He is an unbelievable mover, and his arm works,” said Brett Campbell, the Florida area scout who signed Nunez.
6. Low-A San Jose right fielder Carlos Gutierrez leads the California League with a .352 batting average as he leans into his strong bat-to-ball skills. The 5-foot-10 lefthanded batter signed out of Mexico in 2023 and complements his barrel skills with a discerning batting eye and above-average speed. “You could picture him playing on AstroTurf fields in the ’80s, hitting doubles and triples and stealing bases,” Giants farm director Kyle Haines said.
7. “He has a low pulse rate—doesn’t get rattled. He just needed to work on his coordination because he’s a big guy.” That’s how high school travel team coach Skip Allen described Marlins righthander Josh Ekness. The 23-year-old has the tools to succeed in the role, namely high velocity on his fastball and slider. Ekness didn’t throw enough strikes as a college starter, but now he is making it work as a Double-A reliever.
8. Red Sox outfielder Jhostynxon Garcia entered 2024 at a crossroads as he repeated Low-A. Little more than a year later, the 22-year-old Venezuelan is raking at Triple-A. What changed? The Red Sox praise Garcia’s dedication to sharpening his swing decisions, remaking his body and grinding in the cage. “I think we can use him as a model for really buying into training,” Red Sox assistant GM Eddie Romero said.
9. The Astros have a knack for venturing off the beaten path to find pitchers. Former Missouri righthander Bryce Mayer may be the latest example after Houston drafted him in the 16th round in 2024. The 23-year-old proved to be too much for Low-A hitters to handle, and he earned a quick ticket to High-A in May. “He’s got a good vertical break on his fastball and good extension,” Astros farm director Jacob Buffa said. “He’s in the zone a lot.”
10. Rays 2024 first-rounder Theo Gillen learned in a brief pro debut last summer what he needed to do to succeed in the minor leagues in 2025. Now, he’s more comfortable in his plate approach and in his move from high school shortstop to pro center fielder as he thrives at Low-A Charleston. “He’s taking his walks, not forcing anything. The swing decisions, contact ability and quality are top of the scale,” Rays minor league operations director George Pappas said.
