Dart, 23, exited the Giants' 28-6 loss to the Rams on Monday after his left knee buckled awkwardly following a double tackle by Los Angeles defenders Josaiah Stewart and Byron Young.

Initial reports said Dart had escaped serious injury and only suffered sprained knee ligaments, with coach John Harbaugh saying the quarterback had avoided a "devastating outcome."

However ESPN and The Athletic, citing unidentified team sources, reported Tuesday that further evaluation indicated a serious injury which could sideline Dart for the remainder of the season.

Asked to comment on the reports on Tuesday, Giants coach Harbaugh said only that "evaluations are ongoing."

"We haven't got any final decisions yet," Harbaugh said. "We've learned a lot more. I wouldn't really want to share too much until until decisions get made. That takes more than one person.

"So when we know what direction we're going to have to go or or whatever it might be, we'll announce that. But we don't have that yet."

Dart's injury is one of several to have struck down NFL quarterbacks in the opening two weeks of the season.

On Sunday, Washington Commanders quarterback Jayden Daniels suffered an elbow injury in his team's loss to the Dallas Cowboys while Chicago Bears star Caleb Williams was also injured in a loss to the Minnesota Vikings.

Williams' back-up Tyson Bagent is also facing a potential spell on the sidelines after being placed in the concussion protocol on Sunday.

In week one, Seattle Seahawks quarterback Sam Darnold suffered a glute injury while Minnesota's Kyler Murray suffered a concussion.