With a week to go before opening day, the Mets received some unsettling news when Jacob deGrom experienced tightness in the back of his right shoulder following a throwing session at Clover Park on Thursday, Mets manager Buck Showalter told reporters on Thursday night.

Showalter said he would be surprised if deGrom made his scheduled start on Friday afternoon against the Cardinals, and will have MRI on his sore shoulder after he is re-evaluated on Friday morning.

At the moment, it’s unclear if deGrom will be available to make his scheduled opening day start against the Nationals on April 7.

The hope of course is deGrom is merely dealing with some fatigue or dead arm as camp enters the latter stages. But considering deGrom’s most recent history of arm troubles, it’s hard not to be concerned considering what he means to the club.

deGrom has allowed one earned run with ten strikeouts in five innings over two starts this spring. He did not pitch after July 7 last season due to right elbow soreness. He went 7-2 with a 1.08 ERA in 15 starts last season before going on the injured list.