FOXBOROUGH, Mass. — It’s Jacoby Brissett’s tryout now.

The Patriots third-string quarterback came on in relief against Miami on Sunday after Tom Brady’s top substitute was injured, inheriting a 21-point lead from Jimmy Garoppolo before piloting New England to a 31-24 victory.

A rookie who was drafted as insurance during Brady’s four-game “Deflategate” suspension, Brissett could be making his first NFL start in four days when the Patriots meet Houston on Thursday night.

“When it’s time to go, you just have to make sure you’re ready,” said Brissett, who completed 6 of 9 passes for 92 yards in his pro debut. “Whenever the opportunity comes, you’ve got to make sure you’re ready for it.”

The Patriots have had one of the most settled quarterback situations in the NFL — if not league history — thanks to Brady, who led the team to six Super Bowls, winning four, during his 15-year career. But the job opened temporarily when commissioner Roger Goodell suspended him following an investigation into improperly inflated footballs in the 2015 AFC title game.

After serving two years as Brady’s understudy, Garoppolo was hoping to use the four-game tryout to show he could be a worthy successor to the two-time league MVP — or perhaps play himself into a starting job elsewhere if the 40-year-old four-time Super Bowl champion continued to defy his age.

In the season-opening victory over against Arizona, Garoppolo was good enough to get the talk radio crowd bloviating about whether Brady should get his job back when he returns. (Belichick said from the start that Brady would be the No. 1 QB in Week 5, and has never wavered .)

Against Miami, Garoppolo completed 18 of 27 passes for 234 yards and three touchdowns. But he was knocked out the game late in the first half, when Dolphins linebacker Kiko Alonso drove him to the turf onto his right shoulder.

Garoppolo got up and tried to walk it off, but he soon dropped to his knee. The trainers were called out, and Brissett began warming up on the sideline.

“You hate to see that,” receiver Chris Hogan said. “He worked so hard for this opportunity. I hope he’s OK. I hope he can get back.”

A third-round draft pick who transferred from Florida to North Carolina State as a junior, Brissett missed on his first two passes but completed six of the next seven. The Patriots ran 26 times with nine passes while he was at quarterback, though they were also trying to milk the clock; he ran four times for a net gain of 10 yards himself.

“Jacoby, he handled it like a professional,” receiver Julian Edelman said.

“He’s very poised,” he said, adding with a laugh, “especially for a millennial.”

Brissett, a third-round draft pick, could have two more games to convince Belichick to keep him around when Brady returns from his suspension in Week 5.

The Patriots have often gone with only two quarterbacks on the roster, though Belichick did hold onto Brady as a fourth-stringer after picking him up in the sixth round of the 2000 draft. There are no quarterbacks on the team’s practice squad.

The Patriots could also bring in someone off the street during the week. Edelman, who played quarterback in college at Kent State and threw a touchdown pass in a 2015 playoff game, would likely be used in an emergency if something happened to Brissett.

“I wasn’t even thinking about that,” Edelman said. “I was thinking about what I could do to help Jacoby.”


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