Zack Wheeler has continued to evolve as a starting pitcher, focusing on neutralizing the platoon advantage and improving his effectiveness against left-handed hitters, according to a May 23 announcement. Wheeler, who is returning from thoracic outlet syndrome surgery, currently holds a 3-0 record with a 1.99 earned run average through his first five starts of the season.
The importance of Wheeler’s adjustments is seen in his ability to dominate left-handed batters. This season, he has faced 72 left-handed hitters and limited them to a .156 batting average and .470 on-base plus slugging percentage. Last year, he held lefties to a .193 average over 336 plate appearances. “I always struggled against lefties, and I’ve been throwing against them for so long now, and teams can stack lineups with lefties,” Wheeler said. “I had to figure out something.”
Wheeler’s transformation includes lowering his arm angle over five years in Philadelphia—a change achieved not by altering his arm slot intentionally but by adjusting his body position during delivery. “I didn’t necessarily try to change my arm angle,” Wheeler said. “I think my mechanics just got better.” He explained that becoming more upright in his delivery naturally brought down his arm slot: “Now I’m more square to the plate, so my arm slot’s down… rather than more over the top like that.” He added that this adjustment helped him stay behind the ball for truer pitches: “Because my shoulders are level, I’m probably behind the ball a little bit more, and the ball’s going to stay truer if you’re behind it.”
Alongside mechanical changes, Wheeler diversified his pitch selection against left-handers beginning in 2024 by adding pitches such as the splitter—now used for about 18% of pitches versus lefties—and occasionally introducing front-door sinkers and sweepers down-and-in. Reflecting on these changes with pitching coach Caleb Cotham during offseasons led him away from relying solely on fastballs and cutters up-and-in: “But now, I’m just changing it up just a little bit more. Introducing newer pitches and locations,” Wheeler said.
Since last season began, only five other pitchers have struck out at least as many left-handed hitters as Wheeler’s total of 130; however, none match his strikeout frequency among those facing similar numbers of batters.
The Philadelphia Phillies represent Philadelphia in Major League Baseball’s National League as one of its charter members; they serve local fans through games at Citizens Bank Park—a stadium they have called home since 2004—and engage broader audiences regionally and nationally through community outreach efforts according to the official website.
Looking ahead, observers will be watching how Wheeler continues adapting both mechanics and strategy as he seeks sustained success throughout this season.
