NFL’s Quarterbacks Knocking on Wood : Football: There have been few serious injuries--and only one season-ender--so far this year. The league credits rule changes.

As the final week of the NFL’s regular season approaches, quarterbacks have good reason to smile just a little and knock on wood. Only one starter has been sidelined with a season-ending injury, and only three teams have had their seasons seriously disrupted by injuries to starting quarterbacks.

Except for Indianapolis, which lost promising young Chris Chandler for the rest of the season when he injured a knee in Week 3, the NFL clubs have to consider themselves fairly fortunate.

Last season fractures, sprains and separations threw quarterbacks into the category of endangered species. The Cleveland Browns had three quarterbacks knocked out of action.

This season even Jim McMahon, the doctor’s best friend, hasn’t missed any time because of injuries.

“The league has tried to do everything it could,” George Young, general manager of the New York Giants, said, referring to changing and enforcing rules. “Now people are actually saying there’s too much holding going on. So which way do you want it? I think the league has done a pretty decent job trying to maintain the game as we know it while protecting the passer.”

That’s not to say there haven’t been bruises and strains along the way. Virtually every quarterback has missed some time with an injury, and establishing criteria that determines how serious an injury is has been difficult. Cincinnati’s Boomer Esiason, for example, did not start a game because of a bruised lung. But after his backup, Turk Schoenert, limped off with a sprained ankle during the first series of the game, Esiason finished without being reinjured.

“The league doesn’t have definitive statistics regarding this,” NFL spokesman Dick Maxwell said. “But I think you might want to ask yourself, ‘Has the club’s quarterback situation been affected by injury this year?’ ”

Add another question: Has the team’s ability to play been affected by injury? Using those two guidelines, league observers believe that this has been a pretty good year for quarterbacks.

Actually, the preseason claimed more quarterbacks by injury than the regular season. The Redskins’ Doug Williams hurt his back running on a treadmill in the spring, Detroit rookie Rodney Peete suffered a knee injury, Neil Lomax of the Cardinals hasn’t played a down all season because of an arthritic hip and the Jets’ Pat Ryan suffered a knee injury.

Besides Chandler, the worst news was in Buffalo, where Jim Kelly missed four games (three starts) because of a separated shoulder; in Los Angeles, where the Raiders’ Steve Beuerlein missed time off and on with an injured knee; in Dallas, where Troy Aikman missed five weeks with a broken left index finger; in New York, where Phil Simms missed all of one game and the bulk of another with an ankle injury.

In San Francisco, Joe Montana (sore ribs among other ailments) has missed two starts but probably would have played in both if the 49ers didn’t have Steve Young as his backup. In Chicago, Mike Tomczak suffered bruised ribs but was benched primarily because Coach Mike Ditka wanted to take a look at Jim Harbaugh.

In Cleveland, Bernie Kosar has suffered through shoulder and elbow problems all season, but Kosar has practiced almost every day, played in every game.

“The primary question,” the Giants’ Young said, “is, ‘How many quarterbacks this year had a season-ender? I think there are very few injuries resulting because of anything that resembles a violent hit. I don’t know of any where an illegal shot caused an injury.”