ORCHARD PARK, N.Y.

Tom Brady is as curious as anyone in wanting to see the New England Patriots unveil their new-look group of receivers at Buffalo on Sunday.

“There are always challenges to really determine what kind of team you’re going to be like,” Brady said. “The mental toughness, the work ethic, the core principles and fundamentals of the game have not been tested under game conditions.

“That’s what it’s all about,” the quarterback added. “We all are excited to see where we’re at.”

The Patriots are coming off a tumultuous offseason that left numerous holes in the NFL’s top-ranked offense last year. And that’s not including New England’s brief flirtation with Tim Tebow, who was cut last weekend.

Many of Brady’s familiar security blankets are gone (Wes Welker, Brandon Lloyd and Aaron Hernandez) or injured (tight end Rob Gronkowski). The four accounted for 3,548 yards receiving and 26 touchdowns last year.

In their place is a group of newcomers led by free agent Danny Amendola.

The Bills have a brand new look to them, too, after an offseason overhaul — the latest in the team’s bid to become relevant again after missing the playoffs for 13 straight years.

Doug Marrone is the new coach, and he’s brought in an up-tempo philosophy on offense, led by first-round pick EJ Manuel at quarterback.

“I’d be lying if I’m sitting here saying I don’t expect him to do great things,” Marrone said.

Here are five things to look out for from the game:

BRADY AT THE HELM: For all the changes the Patriots went through, they’re still led by Brady, who enters his 14th season. And when it comes to facing the Bills, Brady has been nearly unbeatable since taking over in 2001.

Over that span, Brady has a 20-2 record against Buffalo, during which he’s thrown 51 of his 334 career touchdowns.

“Same old, same old,” Bills veteran defensive tackle Kyle Williams said. “Everything is going to revolve around No. 12 (Brady) and what he does. … We know affecting him is the best way to beat this team.”

EJ’S DEBUT: Manuel will become the Bills’ first rookie quarterback to start Week 1 directly out of college since Joe Ferguson in 1973.

Selected 16th overall out of Florida State, Manuel was the only quarterback drafted in the first round. The strongarmed and mobile player showed encouraging signs through training camp before hurting his left knee in a 20-16 preseason win over Minnesota on Aug. 16.

Manuel returned to practice Sunday after missing two weeks.

“I definitely feel like I’m caught back up,” he said. “I wouldn’t play the game if I didn’t feel like I was ready to go.