The Mets have activated right-handed pitcher Rafael Montero, who was with on the team's taxi squad as of early this evening, and optioned infielder Eric Campbell to Triple-A Las Vegas. The whole sequence of events has a lot to do with the Steven Matz's short start on Monday night and the Mets' continued reluctance to place Jacob deGrom on either the disabled list or paternity leave.
deGrom left his first start of the season with lat soreness, and he was already slated to miss his next one on Wednesday afternoon because of the injury. Logan Verrett, who has been in the Mets' bullpen, will start in his place. Throw in the workload the bullpen took on when Matz didn't get out of the second inning on Monday night, and it makes sense that the Mets are adding an arm for at least one game.
The Mets will eventually have to make a decision on deGrom. They've avoided putting him on paternity leave because it would prevent them from backdating a disabled list stint to April 9—the day after his start.