Four times earlier this season, Josh Hartle stepped on the mound and stared across at the Harrisburg Senators in the opposing dugout. But on Thursday night, he took the hill with high red socks and an “H” emblazoned on a cap of his own, having made his Nationals organization debut after being acquired Monday as part of the Foster Griffin trade with the Guardians.
Hartle went on to toss 5 1/3 frames of one-run ball with seven strikeouts for Double-A Harrisburg in its 3-2 win over Chesapeake at Prince George's Stadium. The club’s new No. 28 prospect retired the first 13 batters that he faced with the ball leaving the infield only twice and the only run on his ledger came across to score after he was back in the dugout.
The Nationals acquired four prospects -- Hartle, fellow southpaw Will Dion, right-hander Kendeglys Virguez and outfielder Nick Mitchell -- in exchange for Griffin on Monday but in many regards, Hartle was the headliner. For starters, he was the only one to join the club’s Top 30 Prospects list in the wake of his acquisition. But he also offers an advanced feel for pitching, a trait the big league club helped unlock with Griffin, turning him into an All-Star.
More from MLB Pipeline:
• Top 100 prospects | Stats | Video | Podcast | Complete coverage
Entering 2024, Hartle seemed like a lock to go in the first round of the Draft. An All-American at Wake Forest as a sophomore who racked up 140 strikeouts in 102 2/3 innings, Hartle was near the top of many Draft prospect lists before he saw his stuff and command not have quite the same zip in his junior year. He battled through 15 starts and finished with a 5.79 ERA but flashes of that elite arm were enough to entice the Pirates to nab him with their third-round choice.
He appeared in all of one game for the organization before he was flipped to the Guardians in exchange for right-hander Luis Ortiz in December 2024. Cleveland sent the 6-foot-6 Hartle and his funky left-handed throwing motion to High-A to open 2025 and it all clicked -- he posted a 2.35 ERA across 22 appearances and allowed just two homers in 103 1/3 innings en route to winning Midwest League Pitcher of the Year honors.
Hartle opened this season with Double-A Akron and found the advanced hitters at the upper Minors not as susceptible to chasing his expansive repertoire, which features a pair of low-90s fastballs, an above-average slider, an upper-80s cutter and changeup. A trio of clunkers discolor the ERA but the average-against (.263) doesn't lie -- he was getting hit. The tide turned over his final three starts prior to the Deadline, in which he allowed one run over 16 2/3 innings with just five hits -- all singles -- to his ledger.
Overall, there’s still a ton working in Hartle’s favor. Entering his start Thursday, his 55.8 percent ground-ball rate was tops among all qualified Double-A hurlers in 2026. Expand out to the rest of affiliate ball and just one hurler -- the Rockies’ Austin Newton -- is running a higher rate (56.8 percent).
For comparison at the Major League level, only Phillies All-Star Cristopher Sánchez is producing a higher GB rate (57.7 percent). If you’re not going to be a strikeout pitcher, the next best thing is to get the opposition to pound the ball into the dirt -- and often. While there aren’t many crafty 6-foot-6 lefties, Hartle has made it work.
COMPLETE NATIONALS PROSPECT COVERAGE
Sometimes it’s not always the raw stuff that a pitcher brings to the mound but where he plies his craft. Following the Trade Deadline, Hartle will get to do so in a system that has a recent established track record of developing taller left-handed pitchers -- particularly those who don’t light up the radar gun -- into Major Leaguers.
Mitchell Parker and Jake Bennett were both top-five-round Draft selections from the Nationals this decade. The organization acquired southpaw DJ Herz and helped turn him into a big league rotation piece in 2024. Andrew Alvarez was never a highly regarded prospect coming up through the system as a 12th-round pick, but he’s turned into a rock solid swingman.
Where Hartle ultimately fits into that puzzle remains to be seen. While he’s leaving a system known for its pitching development, he’ll continue his upward trajectory in a similarly minded apparatus that remains laser-focused on its future.