Going into the season, the two most talked about pitchers for the Texas Rangers were Jacob deGrom and Jack Leiter. deGrom was fully healthy for the first time since the start of the 2023 season, while Leiter was looking to live up to the hype he had coming out of Vanderbilt. If both could live up to expectations, 2025 would be a season to remember for the Rangers.
However, 18 games into the season, neither of those two is the best performing pitcher on the roster. That honor goes to Tyler Mahle. He's been the unquestioned ace of the staff and a big reason for the Rangers' early success. But just how good has Mahle been in 2025?
Tyler Mahle is carrying Texas Rangers' rotation in April
When the Rangers signed Mahle during the 2023 offseason, the hope was that he could be a mid-to-back-end of the rotation arm. Once he recovered from Tommy John surgery, he could give the Rangers five or six reliable innings a start. However, no one could have predicted he would start 2025 like this. Through four starts, he has an ERA of 0.92 in 19.2 innings with 21 strikeouts to nine walks, a 0.864 WHIP, and an video game-like ERA+ of 422.
The main reason for Mahle's success has been the effectiveness of his fastball. According to Baseball Savant, his fastball run value is currently in the 97th percentile, one of the best marks in the MLB. Despite only sitting at 91.9 MPH, it's stumped hitters, with opposing players having a .062 batting average and a .176 WOBA against it. It also has produced a 41% whiff rate, among the very best marks for starting pitchers' primary heaters.
While his fastball has been his most-used and effective pitch, his slider has also yielded considerable success. It currently sits in the 94th percentile of off-speed run value. At 82.9 MPH, it has held opposing hitters to a .167 batting average and a .227 WOBA.
He's been a big reason why the Rangers have gotten off to a hot start. They are currently 12-7 and sit two games above the Seattle Mariners for first in the AL West. Their pitching is a significant reason for this, having posted a 3.46 ERA, the sixth-best in the majors. They are also top ten in most pitching categories, thanks in large part to Mahle. The Rangers are undefeated in the four games Mahle has started for them.
Mahle's success has also masked the struggles of guys like deGrom and Leiter. While Leiter was decent in his first two starts, he has been sidelined with a blister recently. On the other hand, deGrom hasn't been anywhere near his former self. Through three starts, he has an ERA of 4.30 through 14.2 innings with 13 strikeouts to six walks, a 1.295 WHIP, and an ERA+ of 90. Suffice to say, he's a far cry from when he was winning Cy Youngs with the Mets.
While it's still unknown if Mahle can keep up this dominance throughout the rest of the season, you won't be able to talk about the 2025 Rangers without bringing him up.