SEATTLE -- With no left-handed relief specialists on their 40-man roster, the Mariners moved to fill that need on Thursday by signing free agent Zachary Rosscup to a one-year Major League deal.

The 30-year-old from Clackamas, Ore., posted a 4.76 ERA in 11 1/3 innings for the Dodgers last year, with nine hits, 20 strikeouts and four walks over 17 appearances. He also put up a 1.00 ERA and four hits allowed over nine innings in 11 Triple-A outings.

"When healthy, Zac has swing-and-miss stuff, which has translated at all levels." Mariners general manager Jerry Dipoto said. "We look forward to seeing what he can do with good health and real opportunity."

Rosscup began last year in the Rockies' organization before being claimed off waivers by the Dodgers on July 11. He had three stints on the disabled list with a blister on his left middle finger, inflammation of the same finger and a left calf strain.

The southpaw owns a career 5.21 ERA in 88 Major League outings over five seasons, having previously pitched in 62 games for the Cubs and nine for the Rockies. Rosscup has allowed 13 home runs in 65 2/3 innings, but he has 87 strikeouts to go with 36 walks.

Rosscup carries a career 1.477 WHIP, but he put up a career-best 1.147 mark last year by reducing his walks while posting a career-high 15.9 strikeouts per nine innings. Over the past two seasons, he's racked up 30 strikeouts with just four walks in 19 innings over 27 appearances.

While Dipoto's roster makeover this offseason has focused on exchanging high-priced veterans and players with limited remaining team control for younger prospects, he'll still need to fill some holes with veterans on one-year deals.

Rosscup fits that mold as a lefty specialist who earned just over the Major League minimum of $610,000 last year and was released by the Dodgers in November. The Mariners traded left-hander James Pazos to the Mets, and they allowed Zach Duke to depart in free agency after also releasing veteran southpaw Marc Rzepczynski in midseason.

Roenis Elias is the only other lefty relief candidate on the current 40-man roster, but he's more of a long reliever who could be in the mix for a starting role this spring.

With Rosscup's signing, the Mariners' 40-man roster is now at 38 players.

Greg Johns has covered the Mariners since 1997, and for MLB.com since 2011. Follow him on Twitter @GregJohnsMLB.