New York Mets right-hander Kodai Senga, the major league ERA leader, was diagnosed with a Grade 1 strain of his right hamstring Friday, hours after he was placed on the 15-day injured list.

Senga, who has an MLB‑best 1.47 ERA, delivered 5.2 scoreless innings, allowing just one hit and five strikeouts, before collapsing after covering first base on a routine grounder.

Senga was seen to be making a play at first base after a ground ball hit by Nationals' shortstop CJ Abrams.