ATLANTA (AP) -- Dan Reeves, who has the Atlanta Falcons on the brink of the best record in franchise history, had quadruple bypass surgery Monday and probably will miss the rest of the regular season.

The 54-year-old coach is expected to be discharged Friday and recover in time for the playoffs.Reeves, who had less serious heart problems in 1990 and '91, checked into Piedmont Hospital a day after feeling ill during a 27-17 victory over the New Orleans Saints, which gave the Falcons their franchise-tying 12th victory.

Rich Brooks, the defensive coordinator and assistant head coach, will be the interim head coach for Sunday's game at Detroit. Tears welled in his eyes when he spoke of Reeves' importance to the NFC West-leading Falcons (12-2), who have only five playoff appearances in 32 years before this season.

"We're talking about a guy who has meant everything to this organization," Brooks said. "It's just been a remarkable turnaround. And the one rock-solid, steady ingredient is Dan Reeves."

A team physician, Dr. Charles Harrison, stressed that Reeves did not have a heart attack and there was no permanent damage to the organ.

Harrison said the high-stress world of coaching may have contributed to Reeves' condition. NFL coaches Bill Parcells and Mike Ditka also have experienced heart problems.

Reeves could oversee some preparations for the final regular-season game against Miami on Dec. 27 before resuming normal duties in the playoffs.

"We're very optimistic," said Dr. James Kauten, who performed the four-hour operation. "The function of the heart is normal, he's a strong man and we think he's going to do very well long-term."

Reeves' illness adds extra importance to the Falcons winning their division, which would mean a first-round bye in the playoffs. Atlanta has a one-game lead over San Francisco and can clinch the NFC West with a victory Sunday at Detroit.

"Obviously, we need a bye more than ever because we want our coach back going into the championship round," running back Jamal Anderson said.

Reeves, who had been feeling some discomfort the past several weeks, pulled Harrison aside in the locker room just minutes after the victory in New Orleans.

He told the doctor of a burning sensation in his chest and throat -- symptoms similar to those Reeves experienced before he underwent two, less obtrusive procedures to clear heart blockage in 1990 and 1991 while coaching Denver.

Reeves took two aspirin, flew back to Atlanta with the team, then checked into the hospital at 6:30 a.m. Monday.

"He's just tough as nails and won't say anything to anybody," Anderson said.

Brooks, head coach of the St. Louis Rams for two seasons, will remain in the coach's booth Sunday and focus on defense, though he will oversee some offensive calls. Quarterback coach Jack Burns will call the plays, relaying signals to offensive coordinator George Sefcik.

Reeves is the NFL's winningest active coach and eighth among all coaches with a record of 160-117-1. He was a three-time AFC coach of the year during his 12 years in Denver, taking the Broncos to three Super Bowls during the 1980s.

He is in second year with Atlanta. The Falcons have won 18 of their last 22 games after years of mediocrity, including a 3-13 finish the year before Reeves arrived.

Between stints in Denver and Atlanta, Reeves coached the New York Giants for four years. He was honored as NFL coach of the year in 1993, but was fired after two straight losing seasons and a feud with management over personnel.