The Mariners transferred Brash (elbow) from the 15-day injured list to the 60-day IL on Wednesday.
The transaction frees up a spot on the 40-man roster for lefty Kirby Snead, who was called up from Triple-A Tacoma in a corresponding move. Brash's status remains unclear following a setback with his right elbow a couple weeks ago, but he now won't be eligible to return from the IL until late May.