Steelers star TJ Watt suffered an ankle injury late Sunday afternoon in Pittsburgh’s 27-13 loss to the Philadelphia Eagles.

As Watt tried to reach Eagles quarterback Jalen Hurts in the fourth quarter at Lincoln Financial Field, he suddenly began hopping and favoring his left foot. Watt didn’t appear to be doing anything special before he surfaced, but he was clearly in severe pain and fell to the ground after a few steps.

Watt eventually made it to the Steelers sideline alone and was immediately examined by the team’s medical staff.

Watt reportedly threw his gloves to the ground and walked to the locker room after leaving the medical tent. He did not return to the game. Watt has totaled 40 tackles and 11.5 sacks this season, his eighth with the team.

Steelers head coach Mike Tomlin said after the game that Watt went down with an ankle injury, which Watt later confirmed.

Further details are not yet known and he is expected to undergo further testing in the near future. The Steelers trailed by 14 points when Watt exited and the game was out of reach. Russell Wilson completed 14 of 22 yards and a touchdown for Pittsburgh, which fell to 10-4 with the loss. Najee Harris led the Steelers on the ground with just 14 yards on six carries, and Calvin Austin III had 65 yards on five catches.

Hurts went 25 of 32 for 290 yards with two touchdown passes and scored a third in the Eagles’ win. They are now 12-2 and have won 10 straight. AJ Brown, who later suffered an injury of his own on Philly’s final drive, rushed for a game-high 110 yards and a touchdown on eight catches.

The Steelers, who remain in control of the AFC North, will face the Baltimore Ravens next weekend. Despite the loss, they secured a playoff spot for the fourth time in the last five seasons.