`The Doctor' has made all the right calls in Denver.(Alex Gibbs, Denver's Broncos line coach.)

The year 2000 may be remembered as the year we bade farewell to Walter Matthau, the Microsoft monopoly and the great offensive lines of the Broncos.

One of the most controversial and effective units in the NFL likely never will be the same. Right guard Dan Neil is a free agent. Left guard Mark Schlereth is considering retirement. So is left tackle Tony Jones. Replacing players wouldn't be a big deal, except Alex Gibbs, Denver's remarkable line coach, also is thinking about retirement.

The offensive line went out quietly Sunday against a dominating Ravens defense, but it has been the motor that has powered this team for the last six years. The Broncos have had three different backs rush for 1,000 yards in the last three seasons. Since 1995, when Gibbs and coach Mike Shanahan joined the team, the Broncos have rushed for more yards than any team in the NFL. Gibbs, an NFL assistant for 17 years, has been the oil that runs through the motor.

"Their offensive line coach is the main reason they are successful," says Ravens Pro Bowl defensive tackle Sam Adams, who faced the Broncos twice a season during his days with Seattle. "He picks good athletes, and he coaches them well. They play any running back they want and they still run the ball. They have had lineman after lineman come in there and he just coaches them up."

Consider what Gibbs, the man they call "The Doctor," has done. Almost without exception, linemen were better as Broncos under Gibbs than they were before or after. Jones spent nine years with the Browns and Ravens, but his only Pro Bowl appearance came under Gibbs. The Ravens saw Harry Swayne's production with the Broncos and signed him to a rich free-agent deal. The Seahawks did the same with Brian Habib. Neither was as productive for his new team as was his replacement for the Broncos. Gibbs helped seventh-round draft choice Tom Nalen become arguably the premier center in the NFL.

Gibbs took Matt Lepsis, who was undrafted, and made him into a very effective right tackle. He made a premier guard out of the undersized Neil, whom one offensive line coach said would be hard-pressed to start in any other system. He found a way to get solid production out of Schlereth, a player who had undergone numerous surgeries (the count is 29).

"What he's done is make them better as a group than as individuals," Chargers defensive coordinator Joe Pascale says.