Medlen has pitched effectively out of the bullpen this year, but with Jair Jurrjens struggling and Randall Delgado back in Triple-A, Medlen will get his chance.
"I finally get my opportunity again," Medlen said. "I think I made the most of it the first time around. I've had a pretty decent year so far, and I just kind of want to keep it going and help us win."
Medlen has appeared in 38 games and has a 2.48 ERA in 54 1/3 innings. He has struck out 36 and walked just 13. He made 18 starts from 2009 to 2010, going 6-2 with a 4.31 ERA.
Gonzalez, who was the Marlins' manager from 2007 to 2010, is looking forward to watching Medlen start.
"I think we're all excited to watch him pitch," Gonzalez said. "Hopefully it works and we can build his pitch count and he can lengthen out."
Medlen threw 46 pitches over three innings of relief on Wednesday against the Marlins and has not pitched since. Gonzalez said that Medlen's pitch count will likely stay below 75 or 80 on Tuesday.
Pitch count doesn't concern Medlen. He just wants to throw as many innings as Gonzalez will allow.
"I just want to be effective and go as deep as I can with the pitch count that I'm given," Medlen said. "I need to make them last. I need to be efficient and throw strikes. Hopefully they're effective strikes and I can get some outs and go as deep as I can."