Third-string quarterback Thaddeus Lewis and backup running back Montario Hardesty will start Sunday when the Browns (5-10) visit the Pittsburgh Steelers (7-8) and their No. 1-ranked defense, coach Pat Shurmur said today after practice.

“Part of my childhood dream was to be a starter one day in the NFL,” said Lewis, who will become the Browns' 18th starting quarterback since their expansion era began in 1999. “Who it was against, I didn't have as visual of that. But it's a challenge, and if you don't like challenges, then you're in the wrong sport. It's a great challenge for this football team to go out there, for this offense to go against the No. 1 defense and try to be successful."

Shurmur officially ruled out quarterbacks Brandon Weeden (sprained right shoulder) and Colt McCoy (right shoulder), running back Trent Richardson (left ankle), cornerback Sheldon Brown (concussion) and tight end Jordan Cameron (concussion). Weeden, McCoy, Richardson and Brown suffered their injuries Sunday in the Browns’ 34-12 loss to the Denver Broncos. Cameron was hurt Dec. 16 in the Browns’ 38-21 loss to the Washington Redskins. None of them practiced this week.

Hardesty has compiled 51 carries for 234 yards (4.6 average) and a touchdown. He will start for the first time this season.

“He’s excited,” Shurmur said of Hardesty. “I’ve been happy with Montario and what he’s done this year. He obviously doesn’t have the number of carries that he would have liked, but the ones he has had have been meaningful.”

Shurmur said Brandon Jackson will spell Hardesty, and fellow running back Chris Ogbonnaya will play, too. Jackson has only played in one game with the Browns.

In addition to Lewis and Hardesty entering the starting lineup, second-year cornerback Buster Skrine will start in place of Brown. Rookie Trevin Wade, a seventh-round draft pick, will serve as the nickel cornerback.

“I think both of them have played quite a bit this year,” Shurmur said of Skrine and Wade. “What I would expect them to do is, again, go out there and play winning football and build on the reps that they’ve had so far.”

Brown’s streak of 175 regular-season games played will end. It’s the second-longest streak in the NFL among all active defensive backs.

“It’s killing him,” middle linebacker D’Qwell Jackson said. “To play 11 years and not miss a game, I know he wants to play.”

Rookie Brad Smelley, a seventh-round pick, and veteran Alex Smith are in line to receive more playing time with Cameron sidelined.