[5] On July 20, 2011, Peterson pitched a hitless inning of relief, walking one batter, in a game against the San Diego Padres.

On September 27, when Javier Vázquez made his last Major League start, Petersen gave him a win when he hit a ninth inning walk-off home run off Nationals reliever Doug Slaten off the Bud Light advertisement in right field.

After the signing of reliever Jon Rauch to a one-year deal, the Marlins designated Petersen for assignment.

He currently plays for the Texas Rangers' Triple-A affiliate, the Round Rock Express.

On 3 April 2014, he hit a grand slam in a 7-6 loss to the Oklahoma City RedHawks.