The Seattle Mariners are looking toward 2026 with cautious optimism, especially regarding Bryce Miller’s pitching progress. After an encouraging 2024 season, where Miller posted a 2.94 ERA and 3.58 FIP, his 2025 was hampered by injuries, resulting in a 5.68 ERA over 90.1 innings. With the team facing potential roster changes, Miller’s progress with his slider development will be a critical factor in securing Seattle’s rotation strength and overall pitching resilience.
Miller’s Offseason Focus: Adding Lateral Movement to His Pitch Arsenal
During the offseason, Miller committed to expanding his pitching tricks to regain his prior dominance. Reports indicate he bulked up physically and sought to enhance his pitch variety by working on two new pitches with increased horizontal movement. Previously, most of his throws had under 12 inches of sideways motion, except his sinker. Now, this effort aims to widen the strike zone and present tougher challenges to opposing hitters by diversifying pitch trajectories.
Influence from Bryan Abreu’s Slider Grip Shapes Miller’s Refinement
Seattle Times correspondent Ryan Divish recently revealed Miller’s approach to slider development this spring, highlighting how Miller modeled his grip after Bryan Abreu’s, a relief ace for the Houston Astros renowned for one of the most effective sliders in baseball. Abreu’s slider delivered an opposing slugging percentage of just .290 with a whiff rate exceeding 46 percent last season, a stark contrast to Miller’s former slider metrics of a .438 slugging against and a 39.2 percent whiff rate.
What distinguishes Abreu’s slider is its significant movement: it drops about eight inches more vertically and runs four inches farther horizontally than the league average, both critical to its success. Miller’s slider, meanwhile, had movement close to league norms, limiting its disruptive potential.
Bryan Abreu, K’ing the Side in the 9th. pic.twitter.com/QRwrwF9Nub — Rob Friedman (@PitchingNinja) June 26, 2025
Expanding the Strike Zone Through Enhanced Slider Movement
Miller struggled last season to expand his strike zone effectively. His hard-hit rate against was alarmingly high at 48.6 percent, placing him in the 2nd percentile compared to his peers, while his ability to induce swings outside the strike zone — measured by chase rate — was below average at 25.7 percent (20th percentile). By increasing lateral movement on his slider, Miller hopes to complement his existing fastball and splitter, creating better pitch tunneling and deception to keep hitters off balance.
The Stakes for Miller and the Mariners Rotation in 2026
Among Seattle’s pitchers seeking to bounce back, Bryce Miller carries arguably the most weighty expectations. Entering the offseason healthy after previous injury woes, he aims to demonstrate that he can anchor the Mariners’ rotation. This is particularly important given the looming free agency of key starters Logan Gilbert and George Kirby, which could leave significant holes. Miller’s return to form would provide the Mariners reassurance that their pitching staff remains robust for the coming season.
The evolution of Bryce Miller’s slider, inspired by Bryan Abreu’s proven technique, could ultimately tilt matchups in Seattle’s favor, even challenging strong opponents like the Astros. Should Miller successfully rehabilitate his arsenal and maintain health, the Mariners’ future rotation depth could be less uncertain and more competitive heading into 2026.
Bryan Abreu, K'ing the Side in the 9th. pic.twitter.com/QRwrwF9Nub
— Rob Friedman (@PitchingNinja) June 26, 2025
