The Mariners designated Miller for assignment Friday.
The move corresponds with right-hander Bryan Woo (elbow) being activated from the 15-day IL. Since having his contract selected from Triple-A Tacoma on April 8, Miller has appeared in nine games for the Mariners, posting a 3.09 ERA, 0.77 WHIP and 12:1 K:BB over 11.2 frames. He could draw interest from teams looking to add a right-hander to the bullpen.