Adam Schefter says there should be no concern with Tom Brady being limited in practice as his performance in games is still as good as ever. (0:46)

FOXBOROUGH, Mass. -- New England Patriots quarterback Tom Brady has been limited in three of the past four practices, and he cited his age as part of the reason.

"Football is a contact sport. I wouldn't say I'm a spring chicken anymore," Brady, 42, said with a smile Wednesday. "I'm trying to just feel as great as I can, and we'll see how it goes tomorrow. But I feel pretty good."

There is little doubt that Brady will play Sunday at the Buffalo Bills in a highly anticipated matchup of 3-0 teams. But his limited practice load seems to be part of the "roster management" that Patriots coach Bill Belichick referenced in regard to the team signing free-agent quarterback Cody Kessler on Wednesday.

Brady was limited twice at practice last week, and the only other quarterback on the roster was rookie Jarrett Stidham. Having Stidham handle the regular offense, in addition to the scout team, was a heavy load.

Brady was one of 10 Patriots players who were limited in practice Wednesday, a group that included wide receiver Julian Edelman, who injured his ribs in Sunday's home victory over the New York Jets. X-rays were negative, but Edelman appears to be managing notable pain after he was landed on by 300-pound defensive lineman Henry Anderson.

"He's as tough as they come," Brady said. "He'll do everything he can to get ready to go. When he's not out there, it's definitely noticeable for all of us. Hopefully he can make it. If he can't, the other guys have got to fill in and do the best job they can do. You've just got to prepare for both."

Sunday's game will feature the NFL's two stingiest teams, as the Patriots have allowed an average of 5.7 points per game in wins over the Pittsburgh Steelers, Miami Dolphins and Jets, who are a combined 0-9.

The Bills have allowed an average of 15.7 points per game in victories over the Jets, New York Giants and Cincinnati Bengals, who are a combined 1-8.

Brady is no stranger to New Era Field (formerly Ralph Wilson Stadium), having been the starter for 15 victories at the venue.

"It's a great environment for football," he said. "This will be the toughest game we've faced, and we're going to have to play a great game. To go on the road is tough, and certainly early in the game, after their pregame tailgate when they're a little fired up -- they're pretty loud. We've got to execute early. Starting fast, which we've actually done a good job with all year, is really important this week."