Mason Miller’s High-Velocity Breakout Season

Mason Miller’s High-Strikeout Breakout Season

The Oakland Athletics have seen a shift in the performance of pitcher Mason Miller over the last two seasons. After beginning his career in 2023 in a role that included starting games, Miller transitioned into a relief role in 2024. Across 65 career appearances for the Athletics, he has recorded a 2-5 record with a 2.93 earned run average and 142 strikeouts.

From the rotation to the bullpen

In the 2023 season, Miller appeared in 10 games for the Athletics, making six starts. During that period, he pitched 33.1 innings and ended the year with a 3.78 earned run average, commonly known as ERA. While he recorded 38 strikeouts, he did not record any saves and finished the season with a record of zero wins and three losses. His walks and hits per inning pitched, or WHIP, stood at 1.20 during that initial season.

The 2024 season marked a shift in how the team utilized Miller. He moved entirely to the bullpen, appearing in 55 games without making a single start. This change allowed him to focus on relief outings, resulting in 28 saves for Oakland and a win-loss record of two wins and two losses. In this role, he was able to finish 44 games for the team and recorded a 2.17 FIP (Fielding Independent Pitching).

Elite strikeout numbers

One of the most notable aspects of Miller’s 2024 season is his strikeout rate. In 65.0 innings of work, he recorded 104 strikeouts. This equates to a rate of 14.40 strikeouts per nine innings, which is an increase from the 10.26 rate he posted the previous year. His strikeout percentage reached 41.8 percent in 2024, compared to the 27.3 percent mark he recorded in 2023.

His overall efficiency also improved as he moved into the relief role. His ERA dropped from 3.78 to 2.49, and his WHIP fell to 0.88, meaning he allowed less than one baserunner per inning on average. He allowed 36 hits throughout the 2024 season while limiting home runs to six. His control also sharpened, with his walks per nine innings decreasing from 4.32 in 2023 to 2.91 in 2024.

Addressing speculation

During the 2024 season, Mason Miller was the subject of speculation regarding whether he was tipping his pitches. The San Diego Padres dismissed these claims as they prepared to face the Brewers with their season on the line. Other league developments during this period included Shane Baz leading in pitch clock violations for a second straight season and Ray Kerr of the Atlanta Braves striking out Shohei Ohtani in the NLDS.

Why it matters

Mason Miller’s transition to the bullpen has provided the Oakland Athletics with a reliever who recorded 28 saves and finished 44 games in 2024. His ability to maintain a 2.49 ERA while increasing his strikeout rate to 14.40 per nine innings has made him a productive member of the Athletics' pitching staff. By increasing his strikeout total and lowering his walk rate, he has improved his statistical profile since his 2023 debut. Over his career so far, he has maintained a 2.93 ERA with 142 total strikeouts across 98.1 total innings pitched.