Smyly departed his last start after just three innings because of a blister on his left middle finger that manager Jim Leyland said was the worst one he ever had seen. The DL stint was made retroactive to Monday.
"You can't risk having the skin break open again," said Smyly, who is 2-2 with a 3.96 ERA in his first year in the majors. "Sometimes you get them. When you throw a hundred pitches, you have to make sure you take care of it."
Fister injured his left side during his first start of the season against the Boston Red Sox on April 7. He returned a month later and made five starts before he went back on the DL with the same left side strain.
"I think he's over the hump this time, but we'll see," Leyland said before Detroit's 5-3 victory over the Chicago Cubs in the finale of a three-game interleague series Thursday.
Fister, 0-3 with a 3.15 ERA on the year, threw a side session on Wednesday and said he should be fine on Saturday. The Tigers will make a corresponding roster move to clear space for the right-hander before the game.
"Getting out there this weekend is going to be a good feeling," he said. "Something I've been looking forward to."
The Tigers recalled Ryan Raburn from Triple-A Iowa to take Smyly's spot, and he started at second base against the Cubs. Raburn hit just .146 in 37 games with Detroit before he was sent down on May 29, but he homered in his last game with the Mud Hens.
"He's not the everyday second baseman," Leyland said. "I'm going to play him the way I think he plays best, which is part time."
It was the first game at Wrigley Field for Raburn, who said he cheered for the Cubs when he was a kid, and Hall of Fame second baseman Ryne Sandberg was his favorite player. He responded with two hits, including an RBI double in the second inning.