BOSTON (CBS) — The last time the Patriots faced the Buffalo Bills, Derek Anderson was taking the snap at quarterback.

The Patriots won that Oct. 29 visit to Buffalo, 25-6, with Devin McCourty picking off Anderson late in the fourth quarter and returning it 84 yards for a touchdown to seal the victory.

The New England defense will not have the luxury of facing Anderson on Sunday when the Bills come to Gillette Stadium. Instead, they’ll have to worry about containing duel-threat QB Josh Allen, Buffalo’s promising rookie who ran all over the New York Jets two weeks ago.

Allen was out with an elbow injury when the Pats and the Bills squared off on Monday Night Football in Week 8, and while his cannon of an arm still needs some work, the rookie can run circles around opposing defenses. He’s Buffalo’s leading rusher with 506 yards on just 75 carries, which does not bode well for a New England defense that has been getting gashed on the ground in recent weeks.

Needless to say, the rookie has Bill Belichick’s attention heading into their Week 16 tilt.

“He’s big, he’s fast, he’s got a strong arm, he’s accurate. He can stand in the pocket and throw. He can get out. There’s some designed runs. There’s some quarterback scrambles or some scrambles that are runs or he scrambles and extends plays and throws it. He’s a hard guy to defend,” Belichick said Wednesday. “I mean, he had almost three quarters of their total offense against the Jets. It’s a lot.”

In that loss to New York, Allen accounted for 307 of Buffalo’s 368 yards of offense. That’s bananas.

The Detroit Lions held Allen to just 16 rushing yards on nine attempts last weekend, a game the Bills won 14-13. That’s the first time a team has slowed him down in nearly a month, as Allen almost had three straight 100-rushing yard games prior, picking up 101, 135 and 99 rushing yards against the Jets, Dolphins and Jaguars, respectively

Six of Allen’s runs over the last four weeks have picked up 20 or more yards.

The rookie has his issues in the passing game, throwing just six touchdowns to nine interceptions on the season. He’s also dead last in completion percentage and in passer rating.

But Allen’s arm won’t be the big concern on Sunday. Even with Pro Bowl corner Stephon Gilmore, and New England’s secondary as a whole, struggling over recent weeks, they should be able to keep the rookie QB from beating them deep on Sunday. Given Allen’s issues through the air, they’ll likely force a miscue or two, as Belichick defenses tend to do against a rookie QB. The real concern will be Allen’s legs going against a porous New England run defense that has given up, on average, 7.5 yards per carry over their last three games.

The Patriots have owned the Bills over the last two decades, especially at Gillette Stadium. But if they sleep on Allen’s rushing ability, it could be a much longer Sunday afternoon than it should be.

Tune in to Patriots-Bills on WBZ-TV — the home of the New England Patriots! Coverage begins Friday night with Patriots All Access at 7 p.m., and pregame coverage begins Sunday morning at 11:30 a.m. with Patriots GameDay. The Pats and the Bills kick off at 1 p.m., and after the game tune in to Patriots 5th Quarter on myTV38!