With Aaron Hernandez already out, if Rob Gronkowski has to sit Sunday the Patriots will be real thin at tight end. (US Presswire)

It may be time for some slow breathing, after all. One day after removing Tom Brady from the injury report (right shoulder), tight end Rob Gronkowski landed on it with a hip injury and is listed as questionable for Sunday's game against the Bills.

It's not known how the Patriots tight end suffered the injury, though it would be a big blow if he isn't able to play Sunday. With Aaron Hernandez ruled out with an ankle injury and Kellen Winslow Jr.'s release, the Patriots are down to Gronkowski, Michael Hoomanawanui and Daniel Fells at tight end.

With Hernandez already out, it's hard to project how the Patriots offense would operate if Gronkowski is unable to play.

Even so, the potential loss of Logan Mankins, while less likely to grab headlines, may be the bigger story.

Also listed as questionable with a hip injury, Mankins hasn't practiced this week and has been slow to respond to treatment. Losing him for any game would create an unfavorable situation, but it becomes more pressing up against a Buffalo pass rush that has already amassed nine sacks.

If Mankins, who claims to have played all of last season with a torn ACL, is unable to play, Donald Thomas would likely start in his place.

Here's the rest of the injury report:

Out: Hernandez (ankle), WR Julian Edelman (hand). Questionable: DE Brandon Deaderick (ankle), CB Alfonzo Dennard (hamstring), DL Justin Francis (ankle), Gronkowski (hip), DL Kyle Love (knee), Mankins (hip), OL Nick McDonald (shoulder), CB Sterling Moore (knee), RB Shane Vereen (foot), OL Sebastian Vollmer (back).

Nick Underhill covers the Patriots for MassLive.com. Follow him on Twitter @CBSPats or @nick_underhill.