Mariners piggyback – The Mariners made five roster moves before Monday’s series opener against the White Sox, activated Bryce Miller from the 15-day injured list, and set a flexible piggyback approach with Luis Castillo immediately after Tuesday’s start—while acknowledging the bul
Seattle — The Mariners didn’t wait long to make things feel different.
Before Monday’s series opener against the White Sox. they made five roster moves and. just as importantly. sketched out how they plan to handle Bryce Miller and Luis Castillo in the immediate stretch that begins with Tuesday’s game. The plan is clear in the moment: Miller will start Tuesday, and Castillo will follow out of the bullpen. What happens after that, manager Dan Wilson made plain, is still being worked through.
Miller was activated from the 15-day injured list and made his season debut last Wednesday in Houston. He looked sharp. but a quirky sixth inning—one that included an umpire injury delay and threw off his rhythm at the very end—remains the kind of detail that can linger for a pitcher returning from a left oblique strain.
Castillo is coming off his most encouraging start of the season. That outing came in Houston last Thursday, following a seven-start stretch in which he posted a 7.79 ERA and the Mariners went 1-6.
Between Tuesday and whatever comes next, the Mariners are also weighing the possibility of a pivot reliever in between Miller and Castillo. Wilson said it’s something the team will “look at during the game and see how it rolls,” adding, “yeah, certainly, that’s always a possibility.”
After all. the version of this rotation that the Mariners are leaning on right now comes with a key advantage: they have six healthy starters. They selected Miller and Castillo to make the scheduled start and the follow-up role through the first turn of this new-look plan. It also could have been done again leading into Thursday’s off-day, depending on how the first outing plays out.
But Wilson stressed that the Mariners aren’t committing to any permanent arrangement—no guarantee this will always be Miller and Castillo as the tandem.
“We’re not necessarily committed to the piggyback being permanent, or that it’ll always be Miller and Castillo who are the tandem,” the approach is being treated like something the club is learning. Wilson said, “Again, this is something that is new to all of us. And we’ll kind of learn as we go.”
The reason the Mariners are choosing these two pieces for now comes down to availability and fit. Castillo has been the least consistent starter so far through the season’s one-quarter mark. Miller. meanwhile. missed that entire stretch while recovering from his left oblique strain. but he’s been one of their clearer options to handle a role that’s unusual enough to require adjustment.
The piggyback isn’t without baseball history on either side.
Castillo has only pitched in relief once in his 10-year career. That was during last year’s American League Division Series—the 15-inning marathon in Game 5 against the Tigers, when there was “quite literally no one left.” He finished that game by recording four outs.
Miller has more relief experience, but not since reaching the Majors in 2023. In the minors, there were real questions about whether he would profile better as a starter or reliever. He answered that emphatically—though the caveat is the last 14 months have also been shaped by notable injuries. limiting him to just 19 starts since the beginning of the ‘25 season.
This roster construction also has a cost. Because the Mariners are operating one full-time reliever short. the rotation needs to carry more innings to keep the bullpen afloat. That connects directly to why Ortiz was brought up and Gonzalez was sent down. with Gonzalez having pitched each of the past two days.
Ortiz was acquired from the Dodgers for relief prospect Tyler Gough last November. but he has yet to make his MLB debut. The organization has treated him as a prospect-in-motion: he’s ranked as the club’s No. 24 prospect by MLB Pipeline, and with Tacoma he’s made 15 appearances with a 1.69 ERA, 12 walks and 18 strikeouts.
Wisdom was added to give Wilson another right-handed bench bat. The Mariners also see it as potential backup to Colt Emerson at third base, after Emerson—listed as the No. 1 prospect—was recalled on Sunday and made his much-anticipated debut. The intention is to play Emerson on most days. but the team could still opt to sit him in games against tough lefty starters.
Finally, Davis’s move to the 40-man roster came shortly after the 26-year-old slugger reached an assignment clause date on May 15. Had he not been added, he could’ve asked for his release. Davis has another clause on the Minor League deal he signed last offseason, in which he can opt out on Aug. 1.
Seattle Mariners Bryce Miller Luis Castillo piggyback White Sox roster moves Dan Wilson injured list left oblique strain Ortiz Gonzalez Colt Emerson Wisdom Davis MLB Pipeline Tyler Gough