Despite all the talk about parity, nobody ever said life in the National Football League was fair. What's happening this season in the American Football Conference provides a case in point.

Going into Sunday's play, five teams -- Denver, the Los Angeles Raiders, New England, the New York Jets and Miami -- have 9-4 records. All five deserve to make the playoffs. One won't.

The reason, of course, is because conference play is broken down into three divisions. Each division winner is assured a playoff spot. Thus, either Cleveland (7-6), Pittsburgh (6-7) or Cincinnati (6-7) will represent the AFC Central as the division champion (probably at 8-8) and one of the five teams currently at 9-4 in the AFC East or West will go to the sidelines early.

The Jets, Patriots and Dolphins have the misfortune of being in the East, which also includes the good fortune of playing Buffalo and Indianapolis twice each. The Broncos and the Raiders head the West, with Seattle still not out of contention at 7-6 and San Diego dangerous as ever offensively despite its 6-7 mark.

Once again, the AFC West appears to be the strongest division in the NFL, followed by the NFC East and AFC East. GAME OF THE WEEK

Los Angeles Raiders at Denver, the Broncos favored by 2 1/2. Two weeks ago, at Los Angeles, the Raiders defeated Denver, 31-28, in overtime.

I was surprised by the Broncos' ability to mount a decent running attack against one of the NFL's best defenses. What's impressive is the way Denver is gaining yardage with its running backs out of what essentially is a passing formation, with quarterback John Elway shoveling the ball off to Sammy Winder or Gerald Willhite.

Maybe it's gadgetry, and the sort of thing not likely to be as effective the second time around. But if it takes some of the sting out of the Raiders' pass rush, it could be the difference in Elway having a good day passing. I'm counting on him having a decent outing against Los Angeles. The Broncos' defense will do the rest. Denver usually is a good selection playing at home in an important game when favored by less than a field goal. Give the 2 1/2. SUNDAY'S OTHER PICKS

I'll take Dallas favored by 2 1/2 at Cincinnati and Seattle favored by 4 1/2 at home against Cleveland.

The Bengals' defense has had trouble stopping most opponents. Danny White is having his best season as the Cowboys' quarterback, not necessarily from the statistical standpoint but certainly in terms of cutting down on big mistakes. The same can be said of running back Tony Dorsett. White's only bad performance was at Detroit. Against Chicago, his offensive line gave him no chance.

The number at Cincinnati is a trifle low. It is based on the assumption that the game is more important to the Bengals than it is to Dallas. That might be. But the Cowboys are superior in virtually every department.

Seattle would have to defeat Cleveland, the Raiders and Denver in its last three games to have any chance of making the playoffs. They could do it, even though they have been the biggest disappointment of 1985. Maybe Coach Chuck Knox will open up his offense, now that he is on the edge of playoff elimination.

Both defenses are excellent. The Browns have a fine running game, but their passing is sub-par. Seattle has better balance, with quarterback Dave Krieg less likely to have one of his bad days in the Kingdome. MONDAY NIGHT

Los Angeles Rams at San Francisco, the 49ers favored by 10. San Francisco should overtake the Rams for the NFC West title. It's about time Rams Coach John Robinson benches quarterback Dieter Brock for Jeff Kemp. Either way, San Francisco should win, but the number is too big to play. REDSKINS AT EAGLES

Both teams have a right to be down, emotionally, after disappointing efforts last week. The difference is that Washington has a long shot chance to make the playoffs if the Rams continue to play poorly. Take the Redskins, giving 1. THE LINE

Las Vegas' early week numbers had San Diego 4 1/2 over Pittsburgh, Kansas City 3 1/2 over Atlanta, New England 8 over Detroit, Chicago 20 over Indianapolis, Miami 5 at Green Bay, St. Louis 3 over New Orleans, New York Giants 7 at Houston, New York Jets 9 at Buffalo and Minnesota 6 1/2 over Tampa Bay.