Ben Roethlisberger's concussion Sunday disappeared by Monday. Now, if only the Steelers could erase all the other body blows they have taken as readily.

Starting safety Troy Polamalu is not likely to play, and starting offensive guard Chris Kemoeatu and backup quarterback Charlie Batch will not in what may be a desperation matchup for a playoff spot in Baltimore Sunday night.

"Redemption Sunday, if you will, is coming for us in the form of the Baltimore Ravens on 'Sunday Night Football,' so we're excited about that," coach Mike Tomlin said yesterday. "That medicine is just what the doctor ordered when you look at where we are, having the opportunity to play our rivals on prime-time television."

The Ravens (5-5), may need a win more than the Steelers (6-4) to stay in reasonable shape in the playoff picture, but, when you face your third loss in a row after losing to the Cincinnati Bengals at home and at Kansas City, the stakes are just as high.

A debate will ensue about the readiness of Roethlisberger to return to play after his second concussion, if indeed that was a concussion the quarterback sustained Sunday when struck by a linebacker's knee.

Tomlin called it a "mild concussion" Sunday that showed no signs of injury by Monday.

"I hesitate to use the term 'mild.' Concussions are not anything to be taken mildly. He was symptomatic at the game. That's why after the game he was down with concussion-like symptoms.

"When we were able to do appropriate testing yesterday, he was symptom-free. He felt fine. So we're proceeding with caution, but we will monitor him each and every day this week as we push forward towards game day, because if any symptoms re-occur or he feels less than fine, we're going to act appropriately."

Tomlin said the decision will be made by doctors, such as UPMC neurosurgeon Joseph Maroon, and not by the coach or the quarterback.

"I'm not acting on Ben convincing me of anything," Tomlin said. "We have independent medical experts, Dr. Maroon and company, who are recognized internationally.

"People in our business in this league fly players in from other cities to see those men. We listen to them first and foremost. We've got a great deal of confidence and comfort in their expertise, and, at this point, if they're comfortable in saying he's symptom-free that will be the utmost determinant in terms of how Ben's capable of participating in leading up to this game and also in this game."

The Steelers are so convinced of Roethlisberger's status that they did not pursue a veteran quarterback. They will sign former West Allegheny High School and Pitt star Tyler Palko to their practice squad. He was property of the Montreal Alouettes and had to clear the CFL's 48-hour waiver wait first.

If Roethlisberger could not play or leaves the game with an injury, Dennis Dixon would replace him.

"I've been very pleased with Dennis' progress as a third quarterback," Tomlin said of the second-year player. "That's different, of course, than playing against the Baltimore Ravens on Sunday night television. No question that we would have to do some things to help him. If he plays in this game, and plays extensively in this game, we have to do some things schematically."

Batch will not be lost for the season, as first feared, unless something pops up when he has surgery to repair his broken left wrist today.

Tomlin said surgeons will insert a metal plate into the wrist of Batch, who will miss two-to-four weeks, according to the coach. He will keep a roster spot open for him for the time being. Tomlin said Batch was injured when he threw incomplete to Rashard Mendenhall and braced himself with his left hand as he hit the ground.

"He probably wasn't necessarily aware of it until after he got out of the shower after the game," Tomlin said.

As their kickoffs for touchdowns and losses mount, so does the Steelers' unemployment list. The Steelers signed not one but two special-teams players yesterday and threw two more of their own overboard.

Linebacker Donovan Woods, signed from the practice squad last week, and veteran cornerback Keiwan Ratliff were released. Taking their places are two NFL veterans, cornerback Corey Ivy and linebacker Rocky Boiman.

Ivy, 32, has played for five NFL teams, most recently the Baltimore Ravens, whom the Steelers play Sunday night. He played for Baltimore the past three seasons. He was released by Cleveland after spending this summer in training camp with the Browns. Boiman, 29, has played seven seasons with five teams. He was cut by the Tennessee Titans at the end of training camp.

Ratliff made the Steelers after signing with them as a free agent last spring. Woods last week replaced Arnold Harrison after he was released.

"We're going to be aggressive about solving our ills ... I can assure you that," Tomlin said yesterday.

Is Jack Lambert available?

The Steelers also signed offensive lineman Jonathan Palmer to their practice squad and released running back Justin Vincent.

Tomlin was not happy that some players such as safeties Tyrone Carter and Ryan Clark said they did not get the play call on third down in overtime that led to a 61-yard pass play by the Chiefs.

"Dick LeBeau told those guys what we were going to call on third down before we even took the field that series. OK? So, as far as I'm concerned, knowledge of the call was not an issue in that circumstance."

Other highlights from Tomlin's news conference yesterday:

• He defended the call that pitched the ball deep and wide to Mewelde Moore on third-and-2 at Kansas City's 35 in overtime. "Mewelde's done some nice things for us. I'd do it again.''

• He called the Chiefs' big pass plays Sunday of 30, 47 and 61 yards "disturbing. We were out of place."

• Ramon Foster will start at left guard for Kemoeatu. "For a young guy, he's shown remarkable maturity as a professional."

• Defensive end Travis Kirschke, out three games with a torn calf muscle, may return to play in Baltimore. "You know we're going to need the services of Travis, if we can get [them], in a game like this the way the Baltimore Ravens are capable of running the football."