Source: Rob Gronkowski to play

New England Patriots tight end Rob Gronkowski is expected to play Sunday against the Buffalo Bills despite being listed as questionable with a hip injury, a league source told ESPN NFL Insider Adam Schefter.

Offensive lineman Logan Mankins, one of 10 Patriots players listed as questionable on Friday's injury report, was downgraded to out.

The Pats also downgraded cornerback Alfonzo Dennard (hamstring) and defensive linemen Brandon Deaderick (ankle) and Justin Francis (ankle) to out.

With receiver Julian Edelman (hand) and tight end Aaron Hernandez (ankle) already declared out earlier this week, the Patriots only will have to deactivate one additional player prior to Sunday's game.

Without Mankins, the Patriots are expected to start fifth-year guard Donald Thomas on Sunday. He started the team's Week 2 loss to the Arizona Cardinals, one of 15 career starts.

Also Saturday, the Patriots signed free agent offensive lineman Matt Tennant, who was claimed off waivers by the Pats on Sept. 1, but was waived on Sept. 4 in order to make room for fullback Lex Hilliard.

Originally a fifth-round pick in 2010 by the New Orleans Saints, Tennant, who played at Boston College, can play both center and guard.

Gronkowski has been held to just 156 yards through three games a year after setting an NFL record for receiving yards and touchdowns by a tight end. In a Week 3 loss to the Baltimore Ravens, he was targeted just three times and caught two passes for 21 yards, his lowest totals since Week 4 of 2011.

Gronkowski, though, told reporters Friday that he's not worried about his numbers.

"Always going with what the game plan gives me," said Gronkowski, who grew up near Orchard Park, N.Y., where Sunday's game will be played. "You never know what kind of situations you're going to be in during the game, how the game is going to work out. Whatever the assignment is, whatever I'm asked to do, if it's going out catching the ball, if it's staying in blocking, if it's run blocking, whatever it is, whatever I'm asked to do, I've just got to go out and perform to the best of my ability at that play."

Gronkowski was a new addition to the Pats' injury report Friday. Considering there were no previous reports of a hip injury, it stands to reason that the tight end injured the hip during Friday's practice session.

Information from ESPN NFL Insider Adam Schefter, ESPNBoston.com's Field Yates, ESPNBoston.com's Mike Rodak and ESPNBoston.com's Mike Reiss was used in this report.