Walker was recalled from Triple-A Tacoma and will start against the Yankees on Tuesday.
Walker went just 4-7 with a 4.10 ERA over 17 starts with Seattle before being optioned to Tacoma on Aug. 8. Since being sent down, Walker has pitched three games, posting a 3.60 and 1.33 WHIP over said outings. He's slated to take the mound Tuesday against CC Sabathia and the Yankees. In a corresponding move, Cody Martin was optioned to Tacoma.