The 37-year-old, recovering from two Tommy John surgeries, was acquired to help log some innings while allowing the Marlins to not rush some of their pitching prospects.
Initially, Wolf pitched in relief, because prospect Anthony DeSclafani was given a chance to make two starts. But on Wednesday night, the club announced DeSclafani was being optioned to Triple-A New Orleans.
Wolf now will step into the rotation and make his first start on Sunday against the Brewers, one of his former teams.
As a Marlin, Wolf has thrown five innings of relief. His first relief stint resulted in an unconventional save. Because the lefty threw the final three innings of the game, he was awarded a save in Miami's 13-3 win over the Dodgers.
"It's nice to be back at the big league level and get those innings in," Wolf said. "It's only five innings, but I felt pretty good in those five innings. The biggest thing for me is the physical part."
Prior to signing with Miami, Wolf was 5-1 with a 4.50 ERA in six starts for Arizona's Triple-A Reno affiliate.
"This whole year, I've felt really good physically," Wolf said. "I've felt I've gotten a lot stronger with each start before I got here. That, to me, is a big thing. I feel like if I'm healthy, I've got a good chance to help the team win."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter