The Mets are placing Jacob deGrom on the injured list, manager Luis Rojas told reporters, including Deesha Thosar of the New York Daily News, this morning. He continues to deal with forearm tightness and won’t throw until that subsides.

It’s not an unexpected development after deGrom’s throwing program was halted yesterday. Nevertheless, it’s still a tough blow to a Mets team that holds a meager 2.5 game lead in the National League East. The diagnosis of forearm tightness and seemingly uncertain recovery timeline are even more alarming, given deGrom’s status as the best pitcher in the league.

deGrom has dealt with a few health issues over the course of the season. He missed a couple weeks with side tightness earlier in the year, and he’s also been forced out of starts early with forearm and shoulder soreness. Neither of the previous arm problems required an IL stint, but his most recent injury will land him on the shelf.

When healthy, deGrom has been truly otherworldly. The two-time Cy Young award winner has worked to a 1.08 ERA across 92 innings. He has struck out an incredible 45.1% of opposing hitters, while walking just 3.4% of batters faced. A healthy second half would make him the prohibitive favorite to land a third Cy Young (and perhaps win the NL MVP award), but it’s now unclear when he’ll again take the mound.