New England Patriots fans held their breath when tight end Rob Gronkowski took a big hit in the fourth quarter of Sunday night’s game against the Denver Broncos.

Brady threw a pass intended for Gronk, which caused the Patriots tight end to turn in an attempt to haul in the football. As he did, though, he got drilled by Broncos safety Darian Stewart in his right knee, and was not expecting the big hit, so he landed a bit awkwardly, and the pass was incomplete.

Gronkowski was carted off the field and made his way to the X-ray room. He left shortly after and was able to walk on his own.

No official word on the severity of the injury, but it doesn’t look good.