Peterson is likely to start Friday in Baltimore, Mike Puma of the New York Post reports.
Friday would have been Max Scherzer's turn in the Mets rotation, but he was traded to the Rangers on Saturday and is slated to make his debut for Texas this Thursday. Peterson, 27, has struggled to a 5.92 ERA and 1.62 WHIP in 11 starts and six relief appearances this season with New York.