The 26-year-old Lowe, 1-3 with a 3.48 ERA in 11 relief appearances this season, has lower back disc inflammation, an ailment that has bothered him periodically since last November.
Lowe explained on Wednesday that the disc was putting pressure on a nerve that caused pain in his buttocks and the back of his right leg.
"It could be [healed] within seven days," Lowe said, "but we're going to play it safe. It's something I have been battling. I think after that bunt play [against the Rangers] where I slipped, I think the slide just fired it up.
"I finally went in and thought an MRI would probably be the best thing. So that's what we did."
Kelley, who started the season with the Mariners, was sent to the Minors last week to make room on the roster for left-handed starter Cliff Lee. He made two appearances with Tacoma, allowing two earned runs in 2 2/3 innings.