Peterson will be available out of the bullpen Wednesday and is not scheduled to start either of the Mets' next two games, Tim Healey of Newsday reports.
Peterson owns a strong 3.51 ERA through the first five starts of his big-league career, though his 18.9 percent strikeout rate and 10.4 percent walk rate are both fairly poor. He wasn't great in his first start back from shoulder inflammation Friday, allowing three runs in four innings against the Yankees. It's possible the rookie moves back into the rotation at some point in the near future, pushing either Robert Gsellman or Seth Lugo, who began the year in the pen, back to their original roles, but it will be Gsellman, rather than Peterson, who starts against the Yankees on Thursday.