Mariners pitcher Bryce Miller, who hasn’t pitched in a game since the start of spring training with an abdomen/oblique injury, was scheduled to pitch a 25-pitch standard bullpen today as part of his rehab process. Instead, Miller’s bullpen was cut short after just a few warmup tosses, as Miller reported feeling tightness in the area while ramping up to his bullpen. The Mariners immediately opted to shut him down for the day, though not from throwing in general.

“This is rehab. This is part of that,” said Mariners GM Justin Hollander. “We told Bryce specifically…if you feel anything at all, don’t push through it. That’s not where you’re at in this process.”

Miller got through the on-ramp to his bullpen—stretching, touch-and-feel tosses, throwing around a football and warming up—fine, but felt tightness once he got on the mound and started throwing with more intent. As instructed, he immediately reported the feeling to a trainer, and the Mariners opted to cut the session short.

“We’re not going to push through this and risk actually having to take a step backwards,” said Hollander.

Miller won’t be shut down from throwing; he’ll still play catch, and in another three to four days they’ll try again with the touch and feel bullpen, similar to the one he threw a few days ago. If Miller progresses through all of that without issue, he can move to trying the standard bullpen again, about a week from today. Hollander says that’s just what the rehab process looks like.

“Some days, you feel a little tightness, and we back it down. Sometimes you feel great, and we feel like you’re ready to take the next step. He wasn’t ready to take the next step today, and smartly said, I’m not ready to take the next step today, so we’ll try again in a couple of days.”

The bullpen step is the hardest one to clear, moving from playing catch to throwing with intent and intensity, but it does delay Miller’s timeline by about a week. Hollander wouldn’t decisively rule out Miller, whose last game appearance was February 26th, for Opening Day, but the math isn’t in Miller’s favor with the regular season starting up in just two weeks. All Hollander would commit to acknowledging was that Miller is behind schedule, and that the team will make decisions as necessary.

The Mariners have built depth this spring with both minor-league signings and internal improvements. They’ve brought back Tacoma stalwarts Jhonathan Díaz and Casey Lawrence, both of whom have filled in at the big-league level. Emerson Hancock, who filled in last spring for various rotation members battling injury, has been especially impressive this spring, showcasing consistent improved velocity and an improved sweeper. Off-season acquisition Cooper Criswell has also been working as a starter this spring, and could either start himself, piggyback with Hancock, or serve as longman out of the ‘pen, all roles the Swiss army knife pitcher says he’s comfortable with. And beyond that, the Mariners could even tap into young but polished Kade Anderson, although that seems like a distant third option ahead of their longer-tenured options or Criswell, who lacks options and was looking like a lock to make the roster even before this. Who is your preferred option to fill in for Miller as he works back from his oblique injury? Let us know in the comments.