New York Mets ace Jacob deGrom felt tightness in his right shoulder while throwing long toss and might not be able to make his scheduled spring start Friday, according to manager Buck Showalter.

The timing is far from ideal for the Mets, who open the season in a week, with deGrom slated to pitch in the opener against the Washington Nationals.

Speaking after the team's spring training loss to the Nationals on Thursday, Showalter said deGrom will be reevaluated Friday, and if he can't start against the St. Louis Cardinals, he likely will have an MRI on the shoulder.

"We are going to see how he is in the morning before we scratch him," Showalter told reporters. "But he has to be pretty convincing to pitch him tomorrow. I'll be surprised if he pitches tomorrow -- rain or no rain."

DeGrom, a two-time Cy Young Award winner, got off to a sensational start last season, going 7-2 with a 1.08 ERA over 15 outings. But an elbow injury sidelined him the entire second half.