Pennsylvania is a good place to be a Double-A prospect these days.
With the game’s top overall prospect Konnor Griffin’s recent promotion to Altoona, the Tigers’ Big 3 doing their thing in Erie, Jarlin Susana (WSH No. 3/MLB No. 72) setting the world on fire in Harrisburg and Aidan Miller (PHI No. 2/MLB No. 48) heating up in Reading, the Keystone State is an epicenter for prospect talent these days. In fact, of the 29 Top 100 prospects currently at Double-A, seven of the top 13 – more than half – play in Pennsylvania.
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On the latest MLB Pipeline Podcast, two of those players, Griffin and Miller, joined Jonathan Mayo for extensive conversations to reflect on their seasons and talk about what comes next. First-round picks selected one year apart (Miller in ‘23, Griffin in ‘24) out of the high school ranks, both Griffin and Miller went to one of Pennsylvania’s two big league clubs, the Pirates and Phillies, and thus have long-term futures in the state.
It’s been a cometlike ascent for Griffin this season, who set the world on fire at Single-A and High-A before arriving in Altoona as a 19-year-old on Aug. 19. By that time, he’d leapfrogged the field right to the No. 1 spot on MLB Pipeline’s Top 100 prospect rankings, and the numbers make it pretty obvious why.
Over his first 108 professional games, Griffin hit .329/.410/.512 with 16 homers, 77 RBIs and 63 stolen bases – video game numbers, pretty much evenly split between Single-A and High-A. He’s held his own over his first week at Double-A, and he’s continued to see time defensively at both shortstop and center field, where his elite athleticism and plus arm strength are difference makers.
Griffin told Mayo about some of the adjustments he made early in the year that paid dividends and helped accelerate his ascent up the ladder.
“I started getting spun early on, and I was chasing outside the zone a little bit," Griffin said. "Just not being patient. Not taking my walks when I needed to. Once I learned that, I started having a better idea about the approach I needed. I started getting my pitches to hit, and when I would get walked, I’d try to steal bags. Everything kind of took off from there.”
There was also a slight mechanical tweak Griffin made to his stance, incorporating more movement into his load, that he says helped a great deal.
“I added a little rhythm to my stance, rather than standing there being a statue,” he said. "During my swing, my hands were kind of still. Now I have them starting a little farther back and have a rhythm going, which makes me feel loose, makes me feel comfortable. Even though I was a first-round pick, I knew I had a lot of things to work on. I wasn’t going to be uncoachable."
It’s been a more methodical but linear path for Miller, who reached Double-A at the end of his first full pro season down the stretch in 2024 and has spent all of this year with Reading, where he seems to be progressing through some initial challenges. He slumped offensively early in the year but has really turned things around in August, hitting .365/.466/.654 with 17 extra-base hits and 13 steals. Even during rough stretches earlier in the year, Miller’s speed never slumped: his 50 steals – more than double his ‘24 total – lead the Eastern League.
“This month has been a really good month for me, everything seems to be clicking at the plate, but really the all-around game," Miller said. “It’s been a lot of ups and downs this year. Not the season I wanted, hitting-wise, but its provided a lot of lessons. It’s a tough league to play in. it’s a lot different than A ball. I’m really learning who I am as a hitter, really developing an approach … these guys will spin you to death until you prove to them that you can hit it.”
Just like Griffin, Miller said he had to learn how to adjust his approach to more advanced pitching, especially when it came to offspeed pitches. He said he worked on being more aggressive against spin, to attack those types of pitches earlier in the count before needing to protect against them with two strikes.
"It was just being too passive at the plate. I wanted to really change that, revamp my approach," Miller said. "I think the report on me is, 'flip him over, 0-0 spin, because he's not going to swing at it.' It's not like it's their best breaking ball pitch. They're hittable sliders ... they're in the zone. I was just taking them before, and when you go down 0-1 you kind of set yourself up for a bad at-bat, because the pitcher can do whatever he wants after that."
On the MLB Pipeline Podcast, Jonathan Mayo, Jim Callis and Sam Dykstra are your tour guides through all the unfolding stories and breaking news of baseball's top prospects. Each week, you'll find out about the stars of tomorrow from the guys who know today. Download, subscribe and help others find the show by leaving a rating and review on iTunes or your favorite platform.