The Mets placed Senga on the 15-day injured list Saturday with a left calf strain.
Senga missed the first four months of the year due to injuries to his right shoulder and triceps, and his season debut was cut short Friday after he strained his calf in the sixth inning. He's slated to undergo an MRI on Saturday that will help determine how long he will have to spend on the injured list, though the Mets don't believe the right-hander suffered anything more serious than a strain. Tylor Megill, who is filling in for Christian Scott (elbow), will claim the open roster spot, and the Mets have yet to name a replacement for Senga's place in the rotation.