McClendon said that he expects Jackson to play at least two more rehab games -- one as a designated hitter and another while logging nine innings in the field. The Mariners begin a three-game weekend series in Toronto on Friday.
"Obviously, he's getting closer," McClendon said. "It's close. I'm not sure what day he's coming back, but he's feeling better. I'd still like to see him swing the bat a little bit better and then we'll go from there. ... The ankle is fine. He just has to play and get his timing back."
Jackson, 28, is batting .242 with two home runs and four RBIs in 25 games this season.