Pittsburgh Steelers' Ben Roethlisberger has left pectoral injury

Sept. 21 (UPI) -- Pittsburgh Steelers quarterback Ben Roethlisberger was added to the team's injury report Tuesday with a left pectoral injury.

Steelers head coach Mike Tomlin said he was unsure when the veteran quarterback suffered the injury during Sunday's loss to the Las Vegas Raiders.

"I don't know specifically when Ben got injured in the game," Tomlin told reporters. "I don't know that he does. You know, sometimes just in the midst of competition, adrenaline and so forth, you just don't know. Sometimes things just come up after."

Roethlisberger was sacked just twice in the Steelers' 26-17 loss to the Raiders on Sunday, though he was hit 10 times.

"He took too many hits," Tomlin said. "We can run the ball better. We can get the ball out of his hand quicker. We can stay on schedule and not get behind the sticks and get in situations where the line of the game is so far that that enhances the rush."

The Steelers' injury woes extend beyond the 39-year-old Roethlisberger. Four Steelers players are dealing with groin injuries, including standout pass rushers T.J. Watt and Alex Highsmith.

Linebacker Devin Bush and cornerback Joe Haden also are battling groin ailments that forced them to miss Sunday's game.

"I'm not making any drastic statements about the availability of any of these guys because of the degree of the injury changes, the prognosis," Tomlin said. "And the man himself changes the prognosis. We'll give guys an opportunity that are close enough to help the practice. We'll give them an opportunity to practice during the course of the week.

"And if they practice, we'll look at the quality of that practice or how much they practice and let that be a guide for us in terms of their potential participation. Some more established players can play on less prep than others. ... There are a lot of variables at play, but not overly concerned about it. This is the tightrope that we walk week in and week out."

Tomlin also noted that nose tackle Tyson Alualu was placed on injured reserve with an ankle fracture. Alualu had surgery for the injury Monday. Pittsburgh promoted defensive lineman Henry Mondeaux from the practice squad to replace Alualu.

Steelers wide receiver Diontae Johnson, meanwhile, injured his knee on the final play of Sunday's game against Las Vegas. Tomlin was optimistic about his status moving forward.

"He's looking better, but not to be confused with great," the coach said. "We'll follow him and his health as we get through the week."

The Steelers are set to play the AFC North rival Cincinnati Bengals on Sunday at Heinz Field.