Kiekhefer was claimed off waivers by the Mariners on Friday.
Kiekhefer was stellar out of the bullpen for Triple-A Memphis in the Cardinals organization (2.08 ERA, 2.11 BB/9 in 2016), and although he didn't find as much success at the major league level, his performance still intrigued the Mariners enough to warrant a roster move. The left-hander doesn't overwhelm anyone with strikeouts, but his excellent command could help him vie for a bullpen spot in Seattle out of spring training.