updated 2:57 p.m. ET Oct. 19, 2008

FOXBOROUGH, Mass. - They roam the sidelines, talking into headsets and gesturing at players like all NFL coaches.

Bill Belichick and Mike Shanahan, though, are different. They are two of the top three winningest active coaches in the league — Belichick labeled a defensive genius and Shanahan an offensive expert.

Just how brilliant they are is being tested this season as Belichick's Patriots (3-2) have struggled without Tom Brady and with an inconsistent defense.

Shanahan's Broncos (4-2) have been up and down, scoring more than 30 points in each of their first three games, then struggling without a strong running game that has been a big part of their past success.

The teams meet Monday night; each team has lost two of its last three games.

"You only get 16 opportunities, so they're all important,'' Patriots linebacker Mike Vrabel said. "So whether we've lost two out of three or three out of three, they're all important.''

Since Belichick became coach of the Patriots in 2000, he is 2-5 against Shanahan's Broncos, including postseason games. Belichick's record is 103-35 against all other teams in that span and doesn't have a losing record against any of them.

"Every time we played the Broncos, they had (the Patriots') number, said Denver tight end Daniel Graham, who played with New England from 2002-06. "Shanahan has a great scheme against the Patriots.''

Belichick stresses that it's the players who win or lose games. And without some key players, he and his staff can do just so much.

Brady is out for the season and running backs Laurence Maroney and LaMont Jordan, tackle Nick Kaczur and defensive end Jarvis Green are doubtful for Monday's game. Free agent pickup Deltha O'Neal has been a mediocre substitute for cornerback Asante Samuel, who signed after last season with Philadelphia.

Still, Denver quarterback Jay Cutler is cautious.

"Belichick is one of the best defensive minds in the game and changes it up from week to week,'' he said. "We're just going to wait and see what happens, see that first drive and mix it up a little bit and see how they're going to play us.''

The Broncos use a wide-open passing game. Cutler's strong arm can get the ball deep to receivers Brandon Marshall and Eddie Royal.

Selvin Young, Denver's leading rusher, is questionable with a groin injury that kept him out of last Sunday's 24-17 loss to Jacksonville, although Michael Pittman rushed for 109 yards against the Jaguars.

"By the end of the year, I think it will be more balanced than the way you look at it right now from a statistical standpoint,'' Shanahan said. "I don't think we will ever change our philosophy, but ... we have thrown the ball more than we normally do.''

The Patriots have thrown it less with Brady out with a season-ending knee injury. They have gone from the top offense in the NFL, a record setter, last season to 21st this year.

"Obviously there has been a standard here, a very high standard for however many years,'' said Matt Cassel, Brady's replacement. "Just because we lose a game, I don't feel I should be worried about my job.''

He even got a vote of confidence last week from Belichick.

"He gives our team the best chance to win,'' the coach said. "We have to do a better job than we did against San Diego. But he's our quarterback.''

The Patriots are coming off their lowest-scoring game of the season, a 30-10 loss in San Diego. Cassel was outplayed by a wide margin by Chargers quarterback Philip Rivers. But Rivers was throwing against a defense that didn't sack him or shut down the big play and allowed three completions of at least 48 yards.

O'Neal was burned on two of them. Now he must face a coach he played for from 2000-03.

Shanahan always had "a good running game and a good quarterback and I guess you have to have a good offensive line, too,'' O'Neal said. "So, being there for four years, we always had that and it seems like they're putting that together now.''

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Since taking over the Broncos in 1995, Shanahan is 150-97 in the regular season and postseason, the 17th most wins in NFL history. Belichick, at 145-87, is 18th. Seattle's Mike Holmgren is the only active coach with more victories.

And Belichick leads Shanahan in Super Bowl championships, 3-2.

So why does Shanahan have a much better record in head-to-head matchups?

"I have no idea and I don't think you really think about what you've done in the past. You just get ready for this game,'' Shanahan said. "He's the best in the business and he's proved it over the last how many years. You always look forward to these type of matchups.''

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