Manager Jim Leyland originally targeted that return date earlier in the week, but wanted to see Fister, who has been sidelined since April 7 with a left costochondral strain, get through the outing without experiencing any soreness before making it official.
Leyland traveled to Toledo with pitching coach Jeff Jones to monitor Fister and said the 28-year-old right-hander "passed the test with flying colors health-wise."
"He's a little rusty, but he's ready to go," Leyland said. "He feels totally confident that he's ready to go."
Leyland said the "crispness" wasn't there for Fister, but that's to be expected for a guy who hasn't pitched in a month. The velocity on Fister's fastball hovered around 88-89 mph, a bit slower than usual, but the skipper wasn't concerned about that aspect either.
"Jonesy and I watched him close and he did fine," Leyland said. "His velocity will probably go up another mile or two as we get into it more, but he was fine."
Leyland didn't have a strict pitch count in mind, but jokingly ruled out a complete game.
Fister was 8-1 with a 1.79 ERA after being dealt to the Tigers from the Mariners at the trade deadline last year. His second outing -- exactly a month after his first -- will be his first against his former team.