Pittsburgh Steelers quarterback Ben Roethlisberger will miss Sunday night's game against the Baltimore Ravens because of a concussion he suffered last week, a league source told NFL Network's Jason La Canfora.
The Steelers confirmed that Roethlisberger will serve as the emergency third quarterback. Tyler Palko, the former Pitt quarterback who didn't sign or practice with the team until Thursday, will be the backup despite going through only two practices.
Roethlisberger practiced all week despite sustaining his fourth concussion since 2006 during a 27-24 overtime loss in Kansas City on Sunday. On Thursday, during his only interview of the week, Roethlisberger said he had been cleared to play, joking he passed "thousands of tests."
The Steelers (6-4), losers of their last two and a game behind Cincinnati (7-3) in the AFC North, were so convinced Roethlisberger would play, they did not sign an experienced quarterback even after backup Charlie Batch broke his left wrist a few plays after replacing Roethlisberger on Sunday. Their game plan for the Ravens (5-5) also was built around Roethlisberger playing.
Roethlisberger, however, experienced headaches resulting from the concussion -- his knee struck the knee of Chiefs linebacker Derrick Johnson as he leaned headfirst during a running play in overtime -- and he began debating the wisdom of playing after consulting with the team's medical staff.
Dixon, the former Oregon quarterback who has not played this season, took more snaps than usual in practice Friday -- the first sign Roethlisberger's status might change. Coach Mike Tomlin said Tuesday the team expected Roethlisberger to play, and there were no signs Wednesday or Thursday he wouldn't.
With Dixon at the helm, the Steelers likely will rely mostly on running backs Rashard Mendenhall and Willie Parker and trim the amount of throws Dixon makes. Dixon was an excellent runner in Oregon's spread offense, but the Steelers -- like every NFL team -- limit their quarterback's running because of the risk of injury.
Dixon's only game action came in a mop-up role against Cleveland in the final game of last season. He would be the most inexperienced Steelers quarterback to be thrown into a starting role since rookie Mike Kruczek replaced the injured Terry Bradshaw in 1976. Kruczek went 6-0 as a starter despite not throwing a single touchdown pass and ended his five-season NFL career in 1980 without throwing a scoring pass.
Roethlisberger's apparent decision to not play comes in the same week the NFL has taken a heightened stance on protecting players from head injuries. NFL commissioner Roger Goodell sent a memo to teams outlining steps the league is tasking to reduce head impacts.
Roethlisberger also had two concussions in 2006, one in a motorcycle accident and another last season in that Browns game in which Dixon played.
"It's part of the nature of the beast of playing this game," Roethlisberger said Thursday. "It's a violent, physical contact sport and there's a chance you're going to get hit. You guys don't talk about the bruises we have all over our bodies. If I showed you a bruise on my shoulder and a bruise on my shin, it wouldn't get talked about as much. It's a violent sport we play."
The Associated Press contributed to this report