FOXBOROUGH, Mass. — You are supposed to be a developmental prospect and third-string quarterback who is learning a system, methodically, over years. And then you are called upon to start a game in your rookie year before the New England leaves have begun to turn.

You are facing the NFL’s third-ranked defense, which features J.J. Watt, the greatest defender of a generation.

The standard for quarterback play in your home stadium has been set by arguably the greatest signal-caller in history.

Your team is undefeated and has the potential to win a lot of games—if you don’t screw it up.

The game is televised from the Atlantic to the Pacific and points beyond. It’s even on Twitter.

Your team’s best offensive weapon, a tight end with the wingspan of a pterodactyl, is limited by a hamstring injury and does not catch a single pass.

There is no other quarterback on the active roster to bail you out. The emergency plan is to have a 5’10” wide receiver who played quarterback in college replace you.

You have had only four days since your last game—barely enough time for bruises to turn from purple to yellow.

You have not had a single regular practice as your team’s starting quarterback—ever.

Less daunting circumstances have destroyed more gifted quarterbacks, and not just for the moment.

But somehow, some way, Jacoby Brissett was in his element at Gillette Stadium on Thursday night. You could see it from the time he led his team out of the tunnel, helmetless and at ease with who he is.

New England Patriots quarterback Jacoby Brissett (7) and wide receiver Julian Edelman (11) lead the team onto the field Thursday, Sept. 22, 2016, in Foxborough, Mass., for a game against the Houston Texans. (AP Photo/Elise Amendola)

Between the seamless way the Patriots prepare backups and the way he prepared for his opportunity, nerves were not an issue. “You know we’re part of a great organization, great team,” Brissett said. “A lot of the veteran players helped out and stepped up and helped me a lot. Just giving me confidence; the coaching staff gave me confidence, and everything went from there.”

Brissett warmed up his arm on the sideline before the game and before almost every possession. He must have thrown five times as many passes on the sideline as he did in the game. In a 27-0 Patriots rout of the Texans, Brissett’s statistics—11-of-19 for 103 yards—don’t tell the story of his performance.

This is what tells the story: Brissett’s first start wasn’t about what happened Monday, Tuesday and Wednesday. If he wasn’t comfortable before this week, he wasn’t going to become comfortable in three days.

Even though Brissett had only two walkthrough practices to get ready for the biggest game of his life, he had been preparing for this moment for years.

He was as ready as he could have been.

“You could tell in meetings during the week,” Patriots wide receiver Chris Hogan said. “He was poised and focused, preparing himself as a starter. He was ready for this, even on a short week.”

Brissett came into the game confident, partly because of what happened in his first appearance in an NFL game. Four days before facing the Houston Texans, he replaced injured Jimmy Garoppolo in the second quarter against the Miami Dolphins. He took over with a 21-0 lead, and the Patriots scored another 10 points with Brissett under center in a 31-24 victory.

Brissett didn’t make any highlight plays against Miami, but that was OK because he didn’t make any mistakes that undermined his team.

The Patriots had a plan for Brissett that day. They always have a plan in case their starting quarterback goes down: a separate call sheet with a reduced number of plays.

“[Jacoby] was poised and focused, preparing himself as a starter. He was ready for this.”

— Chris Hogan

Like Brissett, Jim Miller once backed up Tom Brady, playing for the Patriots’ third Super Bowl winner. Charlie Weis was the offensive coordinator on that team, and Josh McDaniels ran the quarterbacks room. Miller recalls a late-season blowout in 2004 when the Patriots wanted to get some work for fellow backup quarterback Rohan Davey.

“They had a package of plays,” said Miller, now a host on SiriusXM NFL radio. “It wasn’t the whole playbook, that’s for sure. Maybe a 10- to 20-play package. And he executed it brilliantly. It’s the way they do it.”

Part of that package for Brissett included this gutsy call from McDaniels, now the offensive coordinator. On 3rd-and-1 on the Texans’ 6-yard line in the first quarter with no score, McDaniels called for Brissett to throw a fade to the corner of the end zone. Not a safe run by wrecking-ball running back LeGarrette Blount that almost certainly would have kept the possibility of a field goal alive, but a difficult throw by the rookie quarterback.

His pass was incomplete, but it showed the belief the Patriots had in Brissett. The offensive game plan was conservative, but McDaniels tried to take advantage of what his quarterback did best.

At North Carolina State, Brissett had rushed for 529 yards his junior year, so the Patriots used quarterback movement plays. On 1st-and-15 late in the first quarter, the Patriots line blocked to the left. Brissett faked a handoff to Blount, then pivoted and ran to his right. He deked one defender on the sideline and squirted into the end zone for a 27-yard touchdown run. At 6’4”, 235 pounds, Brissett on the run is something to see.