The Mariners declined Miller's $6.075 million club option for 2027 on Thursday.
Miller remains under team control through 2029, but the Mariners expect to be able to lock him in at a cheaper cost for 2027 via the arbitration process. The 28-year-old right-hander had an up-and-down 2026 campaign, finishing with a 4.17 ERA, 1.16 WHIP and 119:38 K:BB across 118.2 innings.