Update (5:00 p.m. ET): Gronkowski suffered "what's believed to be a torn ACL," FOX's Mike Garafolo reported after the Patriots' win over Cleveland.
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The Patriots may again have to make do without tight end Rob Gronkowski after he took a vicious helmet-on-knee hit during Sunday's game with the Browns. Gronkowski stayed down for several minutes after the collision with Cleveland safety T.J. Ward, then hobbled onto a cart.
The injury occurred on a 21-yard pass from Tom Brady to Gronkowski. As Gronkowski caught a pass over his shoulder, Ward came flying in low. Gronkowski's leg did not appear to be planted when Ward made contact, but it looked as if it may have hyperextended anyway. Gronkowski's leg also whipped around violently before he hit the turf -- he dropped the football but was down by contact.
Sunday marked just Gronkowski's seventh game of the season. He sat out the Patriots' first six outings while dealing with back and forearm issues. The forearm cost him five games at the end of 2012, too.