Sentiment has no place in betting on professional football. Sentiment is for suckers. Sentiment is for softies who bet with their hearts instead of their heads. Sentiment, in this business, is costly.

I have tried, over the years, always to remember such sound advice. But this Sunday, well, what the heck. On paper, off the recent form, Pittsburgh (6-4) won't cover 6 1/2 points at home against Cleveland (7-3). The Browns are at the top of their game. The Steelers are struggling, what with John Stallworth out for the season, Terry Bradshaw, Jack Lambert and Franco Harris hurting and Sam Davis almost a forgetten name. So what? I'm putting a mythical $250 on Pittsburgh.

The Steelers have been central to Playing Football's uninterrupted stream of success over six seasons. The last two seasons they have been the difference between winning and losing. As a handicapper, I can't forget that. And, as a father, I can't forget an incident that occurred at Three Rivers Stadium quite a few years ago. Pittsburgh was preparing to play Buffalo in the playoffs. In covering the Steelers I had noticed how relaxed and friendly they seemed to be, even to visitors. So I decided to take my son, then 9, along to the press office the morning before the game. Maybe, if he got lucky, he could get an autograph or two as the players came through the front door.

My son was there when Joe Greene came in. Summoning all his courage he asked the huge man for his signature.

"I don't sign autographs," Greene replied, sternly. But before walking off, the great defensive tackle mentioned that he didn't mean to be mean, and maybe a little later something could be arranged to compensate for what obviously had been a big disappointment to the boy. I had to go interview Chuck Noll. Thirty minutes later, on returning to the reception area, my son was gone. He eventually was discovered being taken on a guided tour of the Pittsburgh dressing room by Greene, who sat him down near the Steel Curtain's lockers and proceeded to hold an interview with Dwight White, Ernie Holmes and L. C. Greenwood.

"How are you going to stop O. J. tomorrow?" my son, normally a very shy 9, was asking Greenwood and Greene. Greenwood jumped off his stool, slammed a towel to the floor and proceeded to stomp it unmercifully.

My son got the message -- and the time of his young life that day. O. J. Simpson got the same message some 24 hours later.And I'll never forget that scene, or fail to remember how nice professional athletes can be when they are permitted to be themselves and not placed in the armed camps run by the Al Davises and George Allens of the pro football world.

Nice guys, and considerate organizations, can finish first in the NFL. The Steelers proved that long ago. Greene's Coca-Cola commercial is merely an extension of Art Rooney's basic philosophy toward people.

Mean Joe was the best defensive tackle I ever saw. Now his glory days are gone, and Pittsburgh's defensive front no longer can be counted on to get the job done; certainly not against an offense as diversified as Cleveland's.

The Browns are the logical picks, getting 6 1/2. But there has to be more to handicapping, every once in a great while, than merely analyzing the hard, cold facts and figures. Cleveland can win Sunday, but I'm playing this one for sentimental reasons. Pittsburgh's old pros, their backs to the wall, are going to try to get things together one more time, before it's too late, in an effort to stay in contention in the AFC Central.

It will be pleasant for a change, to have a rooting interest other than purely financial gain. I also will risk $500 this weekend on Baltimore, giving 2 at Detroit, $500 on New England, giving 4 at home to Los Angeles; $500 on Minnesota, giving 4 at home to Tampa Bay; $250 on St. Louis, getting 10 at Dallas, and $250 Monday night on Oakland, giving 2 at Seattle. All I ask in every instance, except Dallas, is that the better team win.

In other games, Las Vegas lists Buffalo 2 at Cincinnati, Green Bay 2 at New York Giants, Houston 4 at Chicago, San Diego 8 over Kansas City, Atlanta 12 over New Orleans, Denver 6 1/2 over New York Jets, Philadelphia 6 at Washington and Miami 8 over San Francisco.