Sources: Giants QB Jaxson Dart out for extended period - ESPN

Jaxson Dart could miss the rest of the season after tests showed that the New York Giants quarterback's knee injury is more severe than initially anticipated, sources told NFL Network's Ian Rapoport and Mike Garafolo.

Dart suffered the injury during the opening possession of Monday's 28-6 loss to the Los Angeles Rams. Coach John Harbaugh said after the game that the Giants likely avoided a «devastating outcome» with Dart's knee.

But sources told Rapoport and Garafolo that the second-year star will miss an extended period of time and is facing the possibility of season-ending surgery.

Harbaugh said Tuesday that evaluations on Dart's knee were still ongoing and declined to comment further on his timeline to return.

«It's an ongoing conversation about the health of a player, of a person,» Harbaugh said on a video call with reporters. «We've got to prepare for the range of possibilities.»

Harbaugh also expressed confidence in backup quarterback Jameis Winston's ability to step in for however long Dart is sidelined.

«We've learned a lot more [about Dart's knee],» Harbaugh said. «When we know what direction we're going to have to go or whatever it might be, we'll announce that. But we don't have that yet, so I don't want to get out over our skis on that.»

The Giants lost Dart on their seventh snap of the game, when he was hit on his right side by Rams linebacker Byron Young. That hit sent Dart into linebacker Josaiah Stewart, who undercut the quarterback's legs, resulting in a hard fall.

Dart immediately grabbed at his left knee and went to the blue medical tent. He walked with a limp to the locker room and initially was listed as questionable to return to the game before officially being ruled out early in the third quarter.