Quarterback Injuries Could Turn NFL Games : Pro football: Status of McMahon, Hebert and Young is expected to be major factor.

Quarterback injuries and comebacks could be changing the face of the NFL this week:

--If Jim McMahon continues to play as effectively on one leg as he did Monday night, the Philadelphia Eagles can still reach the playoffs.

--If Bobby Hebert and Steve Young are as severely injured as some believe, the Rams or the Atlanta Falcons can still move up in the NFC West.

The New Orleans Saints aren’t the same team when Steve Walsh replaces Hebert at quarterback. And the San Francisco 49ers could take another drop with Steve Bono replacing Steve Young, who replaced Joe Montana.

Hebert’s injury, at this point, seems the NFL’s most ominous. Although the Saints think he might have a tired arm after coming back from a full year off, Hebert has the look of an athlete with a shoulder injury, perhaps a rotator-cuff tear.

“I can throw as well as ever--but it always hurts afterward,” he said before practice one day last week at Metarie, La.

That is usually a shoulder-trauma indication--as is the fact that, later in the day, he grimaced slightly after each throw.

The Saints, however, were encouraged when Hebert, without missing a practice minute, kept throwing the ball satisfactorily all week before Sunday’s Ram game.

That he couldn’t play against the Rams a day later suggests that the shoulder was sending a message.

A baseball pitcher with a slight rotator-cuff tear displays all the same symptoms--the ability to throw well for a while, though it hurts, and ultimately the inability to throw hard through the pain.

Hebert has been hurt twice this season, in the Saints’ opener against Seattle and at Philadelphia on Oct. 13, but before Sunday, he had missed only seven quarters as New Orleans won seven consecutive games. The club is 8-1 for the season and 2-0 under Walsh.

After putting Hebert through X-rays last month, the Saints are having the medics take more pictures of his shoulder. On Friday, the team said Hebert will be out for at least two more games.

Otherwise:

--In San Francisco, Young’s knee injury came as the 49ers (4-5) seemed to be making a move toward respectability.

--The Falcons (5-4) have the best mathematical chance to catch New Orleans now, but they will play the Redskins in Washington Sunday, which probably means they will drop to 5-5.

--The Rams (3-6) are facing an even tougher schedule, possibly the NFL’s most difficult from now on, starting with the Kansas City Chiefs Sunday at Anaheim Stadium.

--The Saints, with perhaps the league’s best defense, are sure they can hold their three-game Western lead with Walsh, but they will need Hebert to advance in the playoffs.

--In Philadelphia, McMahon, in a 30-7 rout of the New York Giants, breathed life into the Eagles Monday night, demonstrating the wisdom of last year’s Philadelphia leader, Buddy Ryan.

The only coach in the NFL who wanted McMahon, Ryan brought him aboard when Randall Cunningham, in the midst of a completely injury-free career, thought he could play forever. Ryan thought otherwise. On opening day this year, Cunningham went down with a knee injury.

McMahon, who has himself come back from rotator-cuff surgery, is the lowest-paid quarterback in the league, some estimates putting his salary at $50,000 a game. This time, he beat two Giant quarterbacks getting $3 million a year--combined.

He also beat a $2-million linebacker, Lawrence Taylor, who was out of position on McMahon’s big touchdown pass to tight end Keith Jackson. It was a 73-yard play, breaking up the game.

After replacing Cunningham, McMahon missed several weeks because of his chronic leg injury. It has been another tough year on quarterbacks. They have gone out with injuries in Detroit, Seattle, Pittsburgh, Philadelphia, Phoenix, Green Bay, San Francisco (twice) and other places.

Strangely, the quarterback who, perhaps, has been mauled the hardest and most often, Jim Harbaugh of the Chicago Bears, is still on his feet.

Bear Coach Mike Ditka, after watching the Saints and then the Detroit Lions work Harbaugh over last week and this, said: “He is the ideal Bear quarterback. Does he do everything right? No. Does he do a lot of things right? Yeah. Does he have a lot of guts? Yeah.

“All these people want all these fancy Dans,” Ditka added, meaning Dan Marino, Jim Kelly, John Elway and others on the Bear Fan Club’s most-wanted list. “(The Bears) would run them out of town on a cold Sunday out there.

“(Harbaugh) hangs in there. This guy has got a bazooka in his back pocket. This is infantry stuff. Patton would have been proud of him. (Gen.) Schwarzkopf would have loved him. This is America. (Harbaugh) might be America’s quarterback, I don’t know.”