SEATTLE -- Mariners general manager Jerry Dipoto began the process of adding left-handed relief options to his bullpen with the acquisition of Dean Kiekhefer off waivers from the Cardinals on Friday.
The 27-year-old appeared in 26 games as a rookie with St. Louis in 2016, posting a 5.32 ERA in 22 innings over five different Major League stints. He also pitched 29 games for Triple-A Memphis, where he was 6-1 with a 2.08 ERA and two saves in 34 2/3 innings.
The Kentucky native figures to compete for a spot as a lefty specialist for the Mariners after holding left-handers to a .209 average in 43 at-bats with the Cardinals.
The Mariners will return left-hander Vidal Nuño in their bullpen, but the only other southpaw relievers on the current 40-man roster are David Rollins and switch-pitcher Pat Venditte. Charlie Furbush, who isn't expected back until 2018 following rotator cuff surgery in August, has declined a Minor League outright and opted for free agency.
Kiekhefer was originally selected by the Cardinals in the 36th round of the 2010 Draft out of Louisville. He is 20-16 with a 2.67 ERA in 265 games, including two starts, over seven Minor League seasons.

The 6-foot, 175-pounder fits Dipoto's profile of pursuing pitchers who control the strike zone. He's posted 275 strikeouts and 55 walks in his Minor League career and has issued just 34 walks with 198 strikeouts over his last 286 1/3 innings since 2012.
During that stretch, his 5.82 strikeout-to-walk ratio is tied for the second-highest in the Minor Leagues, while his 1.07 walks-per-nine innings is second-lowest in the Minors among pitchers with at least 250 innings.
With Kiekhefer's addition, the Mariners' 40-man roster now stands at 36 players.
The Mariners claimed right-hander Ryan Weber from the Braves on Wednesday, while losing right-hander Adrian Sampson on a claim by the Rangers.