BALTIMORE -- The Steelers announced this evening that Dennis Dixon will make his first NFL start tomorrow night against the Ravens and that Ben Roethlisberger will dress and serve as the emergency No. 3 quarterback.

Tyler Palko, who practiced with the team for the first time Thursday after he was signed from the CFL, will serve as No. 2.

Roethlisberger experienced post-concussion headaches after he practiced the past week and the Steelers decided to not start him. He left last Sunday's game in Kansas City with concussion-like symptoms.

Doctors conducted additional tests today on Roethlisberger before the Steelers boarded their flight to Baltimore at mid-afternoon and will do so again tomorrow to determine how he feels and if he can play at all.

Although Roethlisberger said on Thursday that he felt fine, passed every test they'd given him and would start against the Ravens, he apparently began having second thoughts yesterday as he developed headaches following practices on Wednesday and Thursday. Roethlisberger left last Sunday's game in Kansas City with what were described as concussion-like symptoms after a blow to his head.

Those symptoms disappeared on Monday and every test administered to him failed to show any symptoms of a concussion.

However, Dixon took most of the snaps in practice on Friday while Roethlisberger took a few here and there.

The Steelers signed quarterback Tyler Palko from the practice squad today to their 53-man roster and he will back up Dixon tomorrow in Baltimore.

Palko's first practice with the Steelers came Thursday after he cleared CFL waivers and was signed to their practice squad. Veteran receiver Shaun McDonald will be released.

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