The Marlins claimed Petersen off waivers Tuesday.
The 30-year-old was designated for assignment by the Dodgers over the weekend, and he didn't make it through much of the waiver order before being claimed. Petersen posted a 6.43 ERA in 14 innings for the Dodgers this season, though he's been dominant at the Triple-A level with a 1.64 ERA, 0.76 WHIP and 44:8 K:BB over 33 frames.