No subject National Football League owners face at meetings this week in Palm Desert, Calif., is more important than steroids.

If public confidence in their sport is of any concern to them, the owners must wrestle with ways to combat the most insidious drug abuse yet. The proliferation of illegal steroids that alter human strength and growth strikes at the heart of athletic competition.

If fans start to believe they are cheering for Frankensteins in shoulder pads, they will soon find it cheaper to go to the movies.

The league already has decided to start subjecting steroid abusers to the same 30-day suspensions upon a second positive test that sidelined 24 players last season for abuse of alcohol, cocaine and marijuana.

Catching steroid culprits is the primary problem. Without unannounced testing, it is practically an exercise in futility. The league claims only 6 percent of its players (about 80) tested positive for steroids during training camp exams last season, but players knew those physicals were scheduled.

At last month's national scouting combine in Indianapolis, only eight of more than 300 college draft prospects (less than 3 percent) tested positive for steroids, but they knew about the test far in advance.

First-time offenders are subject to "reasonable cause" testing, and if they test positive again, they are banned for 30 days. A third violation puts them out for at least a year.

The challenge for the NFL is to stay abreast of medical developments in the use and detection of steroids, no easy task.

"This is a fluid situation," said NFL spokesman Joe Browne.

***** The Chicago Bears say they aren't trying to trade quarterback Jim McMahon, but they obviously would listen if another team called about him.

The bottom line is they would not accept less than a No. 1 draft choice for him, personnel vice president Bill Tobin said.

That's why the various rumors about McMahon's exit don't hold water. No team is eager to give up at least a No. 1 for a quarterback who will be 30 before next season and has been healthy only half the time.

Tobin said New Orleans General Manager Jim Finks, who originally signed McMahon with the Bears, was only joking when he told McMahon's buddy, Kurt Becker, that McMahon was headed for the San Diego Chargers.

"I want to ask Finks what we got for him," Tobin said. "If there were an ounce of truth in it, Finks wouldn't say anything."

It is true that new San Diego assistant coach Ted Tollner is a McMahon fan from days together at Brigham Young, and it is true that the Chargers need a quarterback desperately. It is also true, however, that new Chargers head coach Dan Henning has little use for McMahon and has told Bears coach Mike Ditka and others that McMahon is not the answer to San Diego's problems.

***** - Representatives from Baltimore, Jacksonville (Fla.), Memphis, Montreal, the Carolinas, Oakland and San Antonio have booked rooms in Palm Desert to lobby owners for expansion teams even though there is no expansion committee yet and Commissioner Pete Rozelle has said the league can't justify expansion until a collective bargaining agreement is signed.

- Irony, NFL-style: When the Los Angeles Raiders settled for $18 million from the NFL in their suit, it meant that each of the 27 other teams have to cough up $666,666 apiece to Al Davis.

Then Davis gets to pay players such as former Bears Willie Gault and Otis Wilson.

"He uses our money to pay our players," Tobin said.

- Even though quarterback protection is on the agenda at the meetings, the Pittsburgh Steelers have recommended abolishing the "in-the-grasp" rule, which punishes mobile quarterbacks and is inconsistently enforced.

Anybody can make a rules suggestion. One coach wants umpires to wear helmets because he saw too many of them get knocked down and hurt. But the coach doesn't want his colleagues to know he made the suggestion for fear they would think he's getting soft on officials.

- Instant replay faces another challenge to survival. It needs 21 votes again to stay for the fourth year. If it is approved for more than another "one-year experiment," it will require 21 votes in the future to get rid of it. In the NFL, the minority rules. It takes only eight votes to kill anything.

- Crowd noise is a subject that won't quiet down.

"There is no interest in dampening the enthusiasm of fans," Browne said. "But there is some sentiment that noise has gone beyond acceptable limits and adversely affects competitive equity."

So extra timeouts and 5-yard penalties against the defense will be argued, probably loudly.

- Bernie Masterson Jr., whose dad played with the Bears from 1934-40, has a picture of him wearing a steel face mask attached to a leather helmet at Nebraska from 1931-33, predating previous claims to the origin of the mask. He also remembers his dad explaining how a wooden nose guard worked by holding it in the mouth.

"Instead of breaking your nose, you'd get your teeth knocked out," Masterson said.