His job, as Tom Brady’s backup, is to, first and foremost, do as Tom does.

Hoyer’s got that down pat.

“Brian is always in Tom’s back pocket,’’ said receiver and locker neighbor Julian Edelman. “He’s always following and doing everything that he does: wears the same kind of clothes as Tom, drives the same car as Tom. If Tom has a Vitamin Water, you’ll see Brian with a Vitamin Water or something like that. It’s funny, but Brian does an awesome job.’’

The second thing is to be ready when called upon. It doesn’t happen very often. Brady rarely comes out of games. Even in blowouts, he’s still out there — and throwing — deep into the game.

Damon Huard. Rohan Davey. Jim Miller. Doug Flutie. Vinny Testaverde. Matt Gutierrez. Kevin O’Connell.

Those are the guys who have stood behind Brady since 2001. And most only got to throw a handful of passes spread out over a season.

Other than Matt Cassel, who got his big chance in ’08 with Brady’s knee injury, being Brady’s backup hasn’t exactly been a good career move.

That’s why yesterday was so important to Hoyer. And he knew it.

“It’s just good to get some real game experience and there’s a lot to be learned from that, when those guys are coming at you for real,’’ Hoyer said. “We try to improve every day, especially with our QB coach, whether it’s working on our mechanics or watching, studying defenses, things like that. And that just comes along week to week.

“We just talk about taking advantage of opportunities, and that was the opportunity I was given today.’’

It was an interesting opportunity at that.

Coach Bill Belichick, always thinking, didn’t give Hoyer time to warm up, or put him in at the start of the drive. After the Patriots picked up a first down with 9:26 left in the second quarter, Belichick sent Hoyer in.

“I was just standing there and Bill was like, ‘All right, go in,’ ’’ Hoyer said. “And it was just kind of a spur-of-the-moment thing.’’

Three plays later, before a third-down play, Hoyer was taken out for Brady. Just as if Brady had really been momentarily shaken up. Situational football at its finest.

“Belichick just said you have to be ready, you never know when you might have to be just thrown in there for a couple plays,’’ Hoyer said.

In the second half, Hoyer took over for Brady after the opening drive and led the Patriots on sustained drives each time, going 84, 44, and 73 yards.

Hoyer’s big moment came with 6:39 left in the third quarter on a double fake reverse. After pump-faking a few times, Hoyer and Brandon Tate hooked up on a spectacular 42-yard touchdown pass that ended with Tate laid out on the turf to catch it.

It was Hoyer’s first career touchdown pass and he celebrated like Brett Favre in the Super Bowl against the Patriots — minus the helmet-toting.

“I was just so elated I just sprinted down,’’ Hoyer said.

He made sure after the play that the ball was in safe hands.

“It’s a play that I have a lot of comfort with and Brandon and I had talked about it all week long,’’ Hoyer said. “We hoped we got that play called when we were both in there. He just made a tremendous catch. We’ve got some pretty good chemistry on that play because we’ve run it a lot before, and he made an amazing catch.’’

But the throw by Hoyer will be what many of the scouts around the league will be taking note of.

Hoyer threw it 55 yards in the air flat-footed and while being hit by Dolphins nose tackle Paul Soliai. (Hoyer didn’t see Tate catch the ball; he reacted to the official signaling a touchdown and the roar of the crowd.)

If Hoyer showed anything in his audition, it’s that he has a starting-caliber arm.

“Oh yeah, he definitely does,’’ said running back Sammy Morris, who has seen more quarterbacks than he’d care to recall in his time with the Bills, Dolphins, and Patriots. “That’s the first thing I noticed when he came in, just how much zing he has.

“For being a relatively young guy, he has a good presence in the huddle. He kind of takes command of everything.’’

Arm strength was not a problem for Hoyer when he came out of Michigan State in 2009. After playing behind a poor line as a senior, he had a lot of scouts talking after his combine and pro day workouts.

Still, he went undrafted, and Hoyer still isn’t sure why.

“I don’t know,’’ he said. “I thought things were going great until [draft] day came around, but I’m just thankful to be where I am right now, learning from great coaches, a great player, and fortunately we’ve played well enough to give some other guys opportunities to play in this game. You just have to take advantage of that.’’

The biggest knock against Hoyer coming out of school was inaccuracy. He completed 59.3 percent of his passes as a junior, and with less talent around him as a senior he slipped to 51 percent, with nine touchdowns and nine interceptions.

Hoyer’s performance yesterday (53.8 percent) won’t make those questions go away, even against a good defense. But he showed enough that one wanted to see more.

“He came in pretty confident,’’ said Dolphins cornerback Sean Smith. “He made some pretty good plays out there. I can definitely see why he’s on the roster.’’

Whether other NFL teams have seen enough to want him on their roster is the key question.

Cassel had the benefit of starting 15 games — and winning 10 of them in ’08 — before the Chiefs acquired him and linebacker Mike Vrabel for a second-round pick in ’09.

But Hoyer, who also completed 8 of 12 passes for 71 yards in the season-ending loss to the Texans last season, is well ahead of where Charlie Whitehurst was for the Chargers when the Seahawks acquired him for second- and third-round picks (along with a two-year contract worth $8 million). Whitehurst had taken four NFL snaps and not thrown a regular-season pass before the deal made in March.

Even if Andrew Luck comes out early from Stanford, this is not a good quarterback draft class. It’s probably a stretch to think somebody might come asking about Hoyer this year, but it could happen after the ’11 season.

Hoyer knows that. So while yesterday’s game might have been meaningless for a lot of players, it certainly wasn’t for Hoyer.

“It’s always hard to tell without consistent game experience, but I think from what he’s shown and the opportunities he’s had, he’s done a good job,’’ Morris said. “That was a great ball he threw out to Tate on the touchdown. He has a nice little presence about him. It definitely intrigues you.’’

Greg A. Bedard can be reached at gbedard@globe.com. Follow him on Twitter @greg_a_bedard.