Meisner has been pitching for the Mets' Class A Advanced St. Lucie affiliate. The 20-year-old righty, a third-round pick in the 2013 Draft, went 3-2 with a 2.83 ERA over six starts with St. Lucie.
At the time of the trade, Meisner was ranked by MLBPipeline.com as the No. 15 prospect in the Mets' farm system.
The right-handed Clippard is 1-3 with 17 saves and a 2.79 ERA this season. He will be familiar with the National League East, as he spent seven seasons pitching for the Nationals, with whom he was a two-time All-Star.
William Boor is a reporter for MLB.com. Follow him on Twitter at @wboor. This story was not subject to the approval of Major League Baseball or its clubs.