After nearly four months of games, one thing seems certain about the New England Patriots.

There’s a lot of uncertainty.

Sure, Tom Brady and Rob Gronkowski probably will make big plays and the defense likely will give some up. And, somehow, coach Bill Belichick and his staff will make critical adjustments when problems occur.

But just how good are the Patriots as they start their bye week with a 13-3 record, wins in their last eight games and the AFC’s top seed? Can they make the desired progress once they return from Monday’s day off ? Are they good enough to win their opening playoff game for the first time in three years?

Maybe, but Belichick knows there’s plenty of work left to do.

“Obviously, it’s a good feeling to have a 13-3 regular season,” he said Monday. “(There were a) lot of ups and downs along the way, a lot of challenges that we had to face. There’s certainly a lot of things that we can do better and improve on.”

During the regular season, the Patriots played only two games against teams that finished with winning records and lost both — 25-17 to the Steelers and 24-20 to the New York Giants. Those teams, plus the Broncos, are their only regular- season opponents who made the playoffs.

But the Patriots three losses were by a combined 15 points and two were decided in the final minute. “We’ve got to start strong,” Gronkowski said. “We’ve got to start fast, and we’ve got to play all four quarters.”

The defense hasn’t done that very much. On Sunday, Belichick was still tinkering with his secondary, putting starting cornerback Devin McCourty at safety and giving wide receiver Julian Edelman considerable time in the defensive backfield. The result? Four interceptions.

The Patriots allowed 402 yards against the Bills, dropping their average to 411.1.