It will be the first time he's thrown from the bump since he landed on the 15-day injured list at the beginning of May with right lat inflammation. Brash is eligible for activation from the IL on Friday and has a chance to return on that date, though the Mariners might want to have him make a rehab appearance or two first.

By rule, Ferrer will miss the next 1-to-3 contests while welcoming a new child to the family. His spot on the roster and in the bullpen will be taken over by Domingo Gonzalez.

Miller has been on the injured list since the beginning of the season with a left oblique strain. He's made four rehab starts in the minors since then, allowing three earned runs and posting a 14:7 K:BB over 13.2 innings. He built up to just 61 pitches over five innings during his most recent outing at High-A Everett, so the Mariners may have him on a pitch count during his season debut in Houston.

Mastrobuoni had been in the midst of a rehab assignment with Triple-A Tacoma and appeared to be on the cusp of a return from the 10-day IL, but his move to the 60-day IL likely indicates that he suffered some sort of setback over the weekend. As a result of the transaction, Mastrobuoni now won't be eligible to make his 2026 debut with the Mariners until the final week of May, though an exact timeline for his activation is unclear. The utility player initially suffered the right calf strain in March while playing for Team Italy in the World Baseball Classic.

McGraw's inability to stay healthy has defined his pro career thus far. Selected in the third round of the 2023 draft, McGraw has thrown just 37 innings in pro ball due to consistent elbow injuries — he had Tommy John surgery in 2019 and internal brace in 2023.

Wisdom may have picked up the injury during his last outing Tuesday against the Padres, when he struck out in his lone plate appearance. Wisdom is eligible to be activated from the IL in late April, though oblique injuries tend to take more time to recover from. Rob Refsnyder (personal) was activated from the Mariners' paternity list in a corresponding move.

A strained right pectoral sent Robles to the injured list April 8, and he's now been cleared to return to a game environment after a few weeks of ramping up baseball activity. It's unclear exactly how long the Mariners plan to keep the 28-year-old in the minors, though he isn't expected to require a lengthy rehab assignment.

The transaction clears a spot on the 40-man roster for the arrival of Josh Simpson, who was acquired via trade with the Marlins on Monday. Evans will miss the entire 2026 season after undergoing UCL reconstruction surgery with an internal brace in January.

Vargas has been on the injured list since the beginning of the regular season due to a strained right lat, and his latest setback will require him to restart his throwing progression completely. He won't be eligible to return from the IL until May 23, though it remains to be seen whether he'll be able to return by then.

Wilson may have picked up the injury against the Twins on Wednesday, when he went 0-for-3 with a walk and a strikeout. He'll undergo further tests on his thumb before the Mariners map out a timeline for his return, but a fractured thumb typically means a lengthy stint on the IL. Catcher Jhonny Pereda was recalled from Triple-A Tacoma in a corresponding move.

It's unclear how long Speier has been bothered by the shoulder issue, but he hasn't pitched since last Wednesday and was not sharp in that outing, retiring just two of six batters. Speier has been a workhorse out of the Seattle bullpen, so it's a sizable loss. He's made 15 appearances this season, posting a 2.92 ERA and 12:5 K:BB over 12.1 frames.