Now the decisions become far more difficult for Brian Westbrook and the Eagles.

After suffering his second concussion in as many games over three weeks, the veteran running back must decide what risk he is willing to take to continue his NFL career.

"I've heard a couple different things on that," Eagles coach Andy Reid said when asked about the seriousness of a second concussion in such a short time. "Obviously, it's not a good thing for a second one to happen. I don't know the medical terms of it. I will get that information as we go throughout the week here. I've heard them determine it by if it was a mild hit as compared to a severe hit."

Westbrook wasn't available for comment yesterday and his agent, Todd France, did not respond to an e-mail from The Inquirer.

Reid indicated that Westbrook's second concussion wasn't as severe as the one he suffered last month when he was knocked unconscious by a knee to the head from Washington linebacker London Fletcher. The latest one took place Sunday in San Diego, on the Eagles' first offensive series of the third quarter, when he collided with Chargers safety Eric Weddle.

"He kind of got sandwiched in between Jason Avant coming back and blocking and then Weddle coming up and making a hit," Reid said. "I'm not sure he could get where he wanted to get, so it was a fairly direct hit there. It wasn't a mild hit, I would say."

Westbrook left the field without assistance after the play, and Reid described him as being "foggy."

"He stood up and walked off the field, but you could sense that there was something wrong there," Reid said.

Reid said team doctors evaluated Westbrook after the charter flight from San Diego landed around 3:30 a.m. yesterday. He was scheduled to be evaluated again in the afternoon.

The coach was asked if he regretted letting Westbrook play against the Chargers 20 days after the running back had suffered his first concussion.

"We left it up to the doctors," Reid said. "There's a chance he could have played the week before, and we held him out of that one according to tests and symptoms. He was symptom-free and tests came back normal, and so I did what the experts said. They felt comfortable with it and we went with it."

Reid was asked at his noon news conference if he thought Westbrook would be able to play again this season.

"I think it's too early to tell right now," he said. "It's the last thing on my mind. First thing is that he's OK and that we take care of him. Football right now for Brian Westbrook is not the important thing. It's making sure that we get him analyzed, tested, and taken care of, and then we'll go from there."

Reid said on his show on WIP-AM (610) last night that Westbrook definitely would not play Sunday night against the Chicago Bears.

"Obviously, we're going to check with experts and make sure that we listen to them like we did before," Reid said. "We took every precautionary measure that we could before and it happened again."

One expert - the University of Pennsylvania's Dr. Douglas H. Smith - might argue otherwise. Smith said in The Inquirer's Sunday editions that he didn't think somebody who had suffered a concussion should continue to play football.

Smith, director of the Penn Center for Brain Injury and Repair and a professor of neurology at the school, yesterday described his prophetic advice as unfortunate. After hosting a retreat on the subject of brain injuries yesterday in Radnor, Smith talked extensively about how much more serious the situation had become for Westbrook now that he had suffered a second concussion.

"The No. 1 risk factor for developing Alzheimer's disease is a history of brain injuries," Smith said. "If you want to be a quart low in life . . . and not 100 percent anymore, that's the risk. For me, there is no way."

Smith said the problem with evaluating a concussion was that there was no machine or medical examination that could tell you the severity of the injury.

"We don't have biological markers yet," Smith said. "We're trying. You only have a neuropsychological exam. It won't tell us the rate of recovery or even if you're going to recover. We're really stuck, because if you're seeking advice as an individual, it's hard to find unless you're talking to somebody like me who will tell you not to put yourself at risk."

Smith acknowledged that it could be true that the risk of suffering another concussion was decreased by the amount of time a player rested after the trauma.

"Yes, you probably do recover with time and you do decrease the chance of a worse outcome of another issue, but I can't tell you when," Smith said. "Nobody knows."

And if somebody says he or she does know?

Such people "are not basing their opinion on current facts," Smith said.

Smith said he also understood that the mentality of professional football players might tempt Westbrook to continue his career, as had been the case with so many other professional athletes in contact sports.

"I know you're working with a team, so you have that and a lot of other reasons you want to pull through," Smith said. "You want to prove something to yourself. But in the end, you really have to take this very seriously. This isn't a bad knee or a bad hip. This is huge. This is who you are."