The Mariners placed Munoz on the 15-day injured list Friday with right knee inflammation.
Munoz hasn't pitched since Sunday due to knee problems, and although MRI results on his knee came back negative Tuesday, the Mariners will play it safe and shut their closer down for the year. The 27-year-old didn't quite live up to expectations this season, posting a 4.24 ERA and 1.22 WHIP across 57.1 innings, but he still managed to turn in 28 saves and an 89:24 K:BB. Troy Taylor was called up from Triple-A in a corresponding move.