Is Gronk playing with 'significant pain'? (US Presswire)

Through four weeks, the numbers for Patriots tight end Rob Gronkowski aren't that different than a season ago: 260 receiving yards in 2012 versus 296 in '11; 19 catches versus 18, three touchdowns versus five. Gronkowksi wound up with with 90 catches for 1,327 yards and 17 touchdowns last season. Whether he matches those totals could be determined by his ability to play through pain.

New England lost its other big-play tight end, Aaron Hernandez, to an ankle injury in Week 2's loss to the Cardinals, although he's on pace to return in Week 6. But according to ESPNBoston.com's Mike Reiss, Gronkowski could be the biggest concern for the Patriots. Reiss writes that Gronk has been dealing with "significant pain these last two weeks," including a bad hip and back problems that go back to his college days at the University of Arizona.

Gronkowski was limited in practice this week ahead of Sunday's matchup with the Broncos, and he was used sparingly in the Pats' Week 4 blowout of the Bills. Is this one of those issues that could linger throughout the season or just a garden-variety injury that hundreds of players deal with every week?

More from Reiss: "I wouldn't be surprised if Bill Belichick and his staff are actually more concerned about (Gronkowski than Hernandez) from a health perspective."

For more NFL news, rumors and analysis, follow @EyeOnNFL on Twitter, like us on Facebook, and subscribe to the Pick-6 Podcast on iTunes. You can follow Ryan Wilson on Twitter here: @ryanwilson_07.