FOXBOROUGH, Mass. — When your starting point is immortality, it can be difficult to contemplate a second act.

Patriots cornerback Malcolm Butler was the unlikely hero of last year’s Super Bowl, capping a largely forgettable rookie season with a play for the ages – darting in front of Seattle wide receiver Ricardo Lockette at the goal line to wrestle away the interception that sealed New England’s 28-24 victory.

It was a springboard to fame that few athletes have experienced. The undrafted kid out of West Alabama was soon presenting an award at the Grammys, being handed the keys to the red Chevy pickup truck that quarterback Tom Brady received for being named Super Bowl MVP, giving speeches and making promotional appearances all winter.

But Butler was destined to be more than an overnight sensation. The drama of his big moment was soon replaced by the drudgery of offseason workouts, training camps and an entire season spent battling wide receivers.

His second year as a Patriot saw the indefatigable Butler really make his mark. He was on the field for 1,080 snaps (he played a mere 18 in the Super Bowl), more than any New England defensive player. He was in on 72 tackles, led the team with 15 passes defended, intercepted two more and was selected for his first Pro Bowl.

It is a much more mature Butler that will take the field Sunday when the Patriots try to vanquish the Broncos in the AFC championship game and advance to a second consecutive Super Bowl.

Butler said it’s remarkable how much – and how little – has changed for him in the past 50 weeks.

“A lot of attention, expectations, a lot of judgment,” the 25-year-old Mississippi native said. “But you’ve just got to keep your head down. That’s just me.”

Butler joked that he was “like a baby” to his fellow starters in the secondary – Patrick Chung, Devin McCourty and Logan Ryan. But it became clear as the 2015 season went along that his teammates were increasingly taking their cues from Butler. His no-nonsense approach symbolizes the Patriots’ ethos perfectly.

“I just learned I’ve got to go out there and do the best I can, do anything to help this team win,” Butler said. “And show up when it’s time to show up. It’s been a great honor for me to play with this organization, a lot of success.

“But none of that means nothing unless we do what we have to do.”

That, it went without saying, means winning Super Bowls.

Butler will have his hands full Sunday trying to cover speedy Denver wide receiver Emmanuel Sanders. In the Broncos’ overtime victory Nov. 29, Sanders got the better of the matchup with six catches for 113 yards.

“He can stop on a dime. He can go vertical. He can get in and out of his breaks,” Butler said of Sanders. “You just have to be out there competing every play.”

On the opposite side, Denver will line up the bigger Demaryius Thomas (6-foot-3, 229 pounds). Sanders and Thomas both had more than 1,000 receiving yards this season, but Ryan limited Thomas to a single catch in that previous Patriots-Broncos game.

Still, Patriots Coach Bill Belichick knows the challenge his young cornerbacks will face.

“You can’t just take away one thing. They’re both great catch-and-run players. They can both beat you on intermediate routes, come-backs, in-cuts, slim posts, things like that, and then they’re both great down the field with vertical routes, double moves or just deep patterns, goes, posts, post corners,” Belichick warned. “They can threaten you at all levels of the defense and that’s what makes them a problem.”

In the first meeting, Denver started Brock Osweiler at quarterback. In the rematch, 39-year-old Peyton Manning will be back.

“You’ve just got to play smart. You’ve got to play a full 60 minutes,” said Ryan, a third-year pro who led New England with four interceptions this season. “(Thomas) is going to make some plays. You’ve just got to keep your confidence and keep going at him.”

McCourty said Manning, with his experience, changes the equation for the Patriots’ secondary.

“When he’s out there, no matter what’s in the game plan or what’s not, he’s able to check to different things that he’s seen throughout his time. When Brock was in there it was more (about) running an offense, running (Coach Gary) Kubiak’s offense,” McCourty said. “Whereas Peyton is in, it’s just different variables that you don’t know that he’s getting to that he’s always done throughout his time in the NFL.”

It won’t be Butler’s first chance to match wits with Manning. Butler had four tackles and one pass defensed in a 43-21 victory over the Broncos during the 2014 season.

But this is the game that really matters. It hasn’t taken Butler long to realize what the playoffs are about.

“One-yard run, 12-yard pass, every play counts so you’ve definitely got to be playing at a high level,” Butler said. “It’s the real deal. Win or go home.”

Spoken like a true Patriot.