At some point, the Washington Redskins have to find out how much of the problem is Donovan McNabb. If he isn't the right quarterback for them, they need to know it now so they can figure out what to do next. One way to make a diagnosis is to bench him. McNabb's admirers, both in and out of the locker room, cry that he has been disrespected and scapegoated, but the fact is, scapegoating is part of an NFL quarterback's job description. As Hyman Roth told Michael Corleone, "This is the business we've chosen."

Everybody likes McNabb personally, including Coach Mike Shanahan, who calls him "as classy of a guy that you'll ever meet in your whole life." But where is it written that his job is guaranteed because he's well liked and nice to kids?

The fact is, McNabb has been more classy than good this season. The team has lost five of its last six games, and the offense has been stuck in neutral, and McNabb's responsibility for that has to be assessed. Sometimes, the best way to evaluate is by subtraction. If even Rex Grossman can operate the offense more effectively, then that means the Redskins made a mistake with McNabb. They should shake hands and part with him in the offseason.

Yes, Shanahan could have handled McNabb more gracefully - it's hard to know why he managed the situation so awkwardly, refusing to clarify McNabb's status until late in the week. McNabb's agent Fletcher Smith called it "beyond disrespectful," and there are reports that McNabb's locker room allies are alienated. But that's a secondary issue. Football considerations had to come ahead of public relations, and there is simply no easy way to remove a beloved veteran like McNabb from the lineup.

Shanahan isn't stupid; he knew exactly how big a can of controversy he opened, and he obviously did it because he felt he had to, in order to get some clarity.

"What I'd like to be able to do, is at the end of the season, be able to evaluate where we're at at our quarterback position," Shanahan said. "I told Donovan that there's nothing he could do in the three games that would influence me of what he's done over the last 13 games. . . .

"Right now, I gotta do what I think's in the best interest of this organization. And that's to get a good feel of where we're at at the quarterback position."

The Redskins have to find some explanations for why the offense hasn't performed better. It's a hard thing to analyze. A combination of factors determines whether a play succeeds or fails, and quarterback play is just one of them, but still, it's the most critical.

How much is McNabb contributing - or not contributing? How often does he fail to get the Redskins out of a bad play and into a good one with his reads, his progressions and his decisions? How much of his struggle is due to other failures, such as poor protection, wrong-headed play calls, or an unproductive running game?

We've had 13 games to gather data on McNabb's performance; we have all of his statistics, and he has done nothing to solidify his hold on the position. He has been visibly slow to master the new offense, and made routine plays look hard with his plaguing habit of skipping the ball off the turf. He can be shockingly casual and unfocused. He has made baffling mistakes for a veteran, such as running out of bounds when he needed to keep the clock running, or fumbling the ball on a routine slide. There is something frustratingly sleepy about him, even when he plays well.

It's time to see how the offense operates without him. At a certain point, some things beyond statistics can be examined only in his absence. For instance, McNabb had one of his best statistical performances of the season last week against Tampa Bay, with two touchdown passes and no interceptions, and a strong 75-yard drive in the final 3 minutes 39 seconds of the game. The running game also worked better than it has all year, and the line gave everyone the protection they needed.

Yet the Redskins still lost, 17-16. How much of that was due to what McNabb didn't do? How many points did he leave on the field, when he took a delay-of-game penalty on the 2-yard line to end the first half, or failed to find Chris Cooley in his progressions, or presided over too many three-and-out possessions?

According to some, offensive coordinator Kyle Shanahan is not convinced McNabb is a good fit for his schemes. On the other hand, maybe Kyle Shanahan has failed to play to his quarterback's strengths, as McNabb hinted earlier this week.

"I've been in this league long enough where you can tell when you are not yourself, watching [film] later on, 'Okay, that's something I'm used to doing or I'm comfortable doing.' That's part of the communication that we've gotten better with. There were a lot of factors into that."

If so, then the head coach needs to sort that out - even if it means admitting that he made a terrible mistake. Even if it means accepting that trading two draft picks for McNabb was a bad deal. What the Redskins need now is more information. They need some answers - answers McNabb has failed to give them.