HOUSTON — Ryan Fitzpatrick, who was 4-5 as the Houston Texans’ starting quarterback before being benched, has returned to the lineup after the team ruled Ryan Mallett out for the season with a torn pectoral muscle.

Fitzpatrick will start Sunday’s home game against Tennessee, a team he helped beat 30-16 last month.

The Texans had lost three of four games entering their bye week when O’Brien elected to replace Fitzpatrick with the untested Mallett.

In the first start of his career, Mallett responded with two touchdowns in a 23-7 victory at Cleveland.

In his second start, Mallett wasn’t the same quarterback. He was off target from his first throw on, finishing 21-of-45 for 189 yards, no touchdowns and one interception.

What began as a sore chest for Mallett ended with the torn muscle. He tried to keep it as quiet as possible, according to his teammates, but some of them knew something was wrong.

“I did, but I didn’t have any idea about how serious it was until after the game,” wide receiver DeAndre Hopkins said. “Him playing through that speaks a lot about his toughness.”

O’Brien declined to discuss anything about Mallett’s injury on Monday, saying he was still being evaluated, but that didn’t keep some of his players from offering opinions on their quarterback.

Hopkins was asked if he thought Mallett should have taken himself out of the game because of his injury.

“We had a chance to win the game,” Hopkins said. “We were never out of it with him in the game. I don’t feel like it was a negative situation.”

“It was his second start. He wanted to win. You could see it in his eyes. He never showed us he was hurt, and he never let down on the sideline. He was the same Ryan.”

Mallett’s teammates were impressed with his mental and physical toughness once they learned about his injury.

Inside linebacker Brian Cushing can sympathize with what Mallett is going after suffering season-ending knee injuries in 2011 and 2012.

“That’s a pretty significant injury, and for him to push through something like that says a lot about him as a player and as a person,” Cushing said. “He’s a tough kid. It’s unfortunate. He showed a lot of guts.”

Veteran quarterback Thaddeus Lewis, who played for coach Bill O’Brien at Duke, is being signed to join Fitzpatrick and rookie Tom Savage.

Notes: RB Arian Foster, who missed the last two games because of a groin injury, is expected to return to practice and play against Tennessee.

REPORT CARD VS. BENGALS

–PASSING OFFENSE: C – After the game, it was discovered that Ryan Mallett had played with a torn pectoral muscle, which would explain his lack of accuracy. He was off target from his first to his last pass. He finished with 21-of-45 for 189 yards and one interception. He was sacked once. His longest completion was 22 yards. He didn’t complete another pass longer than 16. This grade reflects the injury.

–RUSHING OFFENSE: F – The Bengals entered the game ranked 28th against the run. They were determined to stop the run and force Ryan Mallett to throw. Arian Foster missed a second consecutive game with a groin injury. Alfred Blue, who had 36 carries for 156 yards against Cleveland, was limited to 46 yards and 2.9 yards a carry. The offensive line didn’t do a good job of run blocking, especially in the first half. Mallett was unable to complete enough passes to force the Bengals to use more defenders in coverage.

–PASS DEFENSE: C-plus – Andy Dalton was 24-of-35 for 233 yards and one touchdown. He relied heavily on a quick drop and a quick release with shorter routes, which kept him from getting sacked. A.J. Green caught 12 passes for 121 yards but averaged only 10.1 yards a catch. Mohamed Sanu caught a 6-yard touchdown pass but averaged only 9.6 yards a catch. Cornerback Johnathan Joseph provided the only Texans touchdown on a 60-yard interception return. Dalton was blitzed and tried to find Green, but Joseph stepped in front of him. Cornerback A.J. Bouye, starting again in place of the injured Kareem Jackson, was pulled when he kept allowing completions. Darryl Morris replaced him.

–RUSH DEFENSE: B-minus – The Bengals ran 43 times for 139 yards, a 3.2-yard average. If you subtract rookie running back Jeremy Hill’s 30-yard run in the fourth quarter, the Texans allowed 2.3 yards on the other 42 carries. Nose tackle Ryan Pickett and ends J.J. Watt and Jared Crick played the run well, as did the linebackers. Crick was in on a career-best nine tackles.

–SPECIAL TEAMS: C – Randy Bullock kicked field goals of 36 and 25 yards. Shane Lechler had a 47.2-yard gross and a 43.2-yard average. The Texans’ punt coverage, meanwhile, was good. Bengals’ kick returner Adam Jones averaged only 6.7 yards per return. He averaged 28 yards on three kickoff returns.

–COACHING: C – With a quarterback playing with a torn pectoral muscle, Bill O’Brien and his coaches kept the Texans in the game until Mike Nugent kicked the Bengals’ last field goal with 1:55 left to make it a two-score game. They turned a 16-3 third-quarter deficit into a 16-13 game in the third quarter before Nugent kicked 31- and 49-yard field goals in the fourth.