The bomb is coming back to the National Football League.

Explosively . . .

The trend was hardly noticeable, the first week of the regular season. The second week, a few of the quarterbacks became a little braver. Then, last Sunday - boom! boom! boom! - and heaven-help the secondary.

This is going to be a long embarrassing season for the cornerbacks and the safeties. NFL officials designed it that way. A pass receiver can be "chucked" only within five yards of the line of scrimmage. After that he is free as a bird to go winging down the sidelines or out over the middle.

More important, the secondaries no longer are receiving the important help they need the most, from the pass rush. The NFL also changed the rules to give offensive linemen more freedom with their hands while restricting the use of hands by defensive linemen.

As a result, passers are getting more time to throw. They are able to go deep, repeatedly, against the same kind of zone coverages that all but eliminated the long pass from the playbook the last several years.

Only a fraction of a second is involved, perhaps, in the extra amount of time the passer now enjoys. But it is an all-important fraction. The league's best defensive fronts suddenly are not able to apply as much pressure as they did. They are not getting to the quarterbacks.

It is a slightly different game being played right now. We are going to see more and more teams reinstate the Bomb Squad as they progress through the schedule.

I wish I could use this development as an excuse for what happened to my selections last week. But that would be misleading. I was bombed out losing with six of seven picks at $250 each, thereby turning a profit margin of $225 through the first two weeks into a net loss of $1,175.

All mythical, naturally.

Atlanta, Miami and San Diego had the point spread beaten last week, late in the game, only to blow it. Pittsburgh stood up. Houston, giving 10, led by 11 in the third quarter, but won by one. New England, with Steve Grogan, played horribly. And Pat Haden, of all people, suddenly found time to throw deep almost anytime he felt like it against Dallas, of all defenses, as poor Benny Barnes was destroyed by Ron Jessie. (Alas, Barnes likely will be on the Dallas bench this week.)

As I said, the rules changes are going to make many teams adjust on defense, and force many handicappers to add a new factor to their figures. Total yards gained passing is going to climb.

I don't like this change. It cheapens the game. But the fans undoubtedly approve.The majority of the spectators enjoy watching race-horse receiveres performing on a freer rein.

The season is young. Take each week and each game separately. Don't expect to see drastic changes in our "defensive" approach to "Playing Football," but keep watching for the bombs and concentrate on why they are exploding all over the field.

This week's picks are Pittsburgh giving eight points at home against Cleveland: Oakland giving four at home against New England, and Minnesota getting 1 1/2 Monday night in Chicago.

The Steelers have their offense running smoothly and their defense should be able to shut down Cleveland's running game. The Browns get the most out of their material but they are overmatched up front both ways. Take Pittsburgh for a mythical $500 even though the line is designed to attract Cleveland money.

Oakland should be able to force Grogan into another poor effort. How much longer can Chuck Fairbanks wait to insert Tom Owen? Grogan misses Daryl Stingley and he desperately needs Russ Francis to get back into action. The Patriots will have their hands full against Ken Stabler and Mark van Eeghen. Risk another mythical $500.

"You and I must be the only people in the country who like Minnesota over Chicago," Bob Martin, the Head Linesman, said yesterday from his headquarters in Las Vegas. So be it. Chicago is 3-0 without intimidating anybody, although Golden Richards cetainly helps the Bear passing attack. Minnesota has had tough luck all three of its games, is 1-2, and could be 0-3, or 3-0. The Vikings know they must win this one or their season threatens to be over quickly. String along with Minnesota for a mythical $250.

In other games Martin lists Washington seven over the Jets, Atlanta one at Tampa Bay, Buffalo six over Baltimore, Denver 7 1/2 at Kansas City, Seattle four over Detroit, San Diego 11 over Green Bay, Los Angeles two at Houston, Miami three at Philadelphia, Cincinnati 6 1/2 over New Orelans, Dalls 17 over St. Louis and the Giants 4 1/2 over San Francisco.