Colts quarterback Peyton Manning will miss four-to-six weeks after undergoing surgery on Monday to remove an infected bursa sac from his left knee.

As a result, he possibly could miss all of the preseason, and perhaps the regular-season opener on September 7.

Team president Bill Polian said that Manning had been receiving treatment for an inflamed bursa sac since February.

The real question, as we see it, is whether the estimate provided is real, or whether Manning’s situation will mimic that of receiver Marvin Harrison, who always seemed last year to be a week away from playing, but who never was able to perform.

Look at it this way — Manning’s problem has been around for five months.  Though removal of the sac could go a long way toward solving the problem, there’s no guarantee at this point that Manning will be back to 100 percent any time soon.

And if the Colts suddenly jump into the bidding for Brett Favre, it would be a clear sign that the situation is more serious than advertised.

We’re kidding.  We think.