The National Football League has a system for figuring out which teams qualify for the playoffs leading to the Super Bowl. The system is easily understood by nuclear physicists, Henry Kissinger and everyone who has memorized the SALT treaties. Lesser mortals put in a telephone call to Fran Connors, the NFL's designated explainer.

In the last month, Connors estimates he and his helpers in New York have received 500 calls from the media and fans wanting to know what teams have to do to make it into the playoffs.

Connors explains the possibilities, all of which begin something like this: "If Oakland beats Seattle and if Denver beats San Diego, then if Miami beats New England . . ."

And so on.

"My life for the last month has been one big 'if,'" Connors said yesterday.

Public rellations men from NFL teams also have called Connors, presumably to pass the information on to their coaches, who in these last two or three weeks know it can be important not only to win but to win by a certain number of points -- for the measure of superiority as reflected by point difference is one of the tie breaking factors in the NFL's laundry list of tie breakers to be used when teams have identical won-lost records.

It also matters what a team's division record is, what its conference record is, how many touchdowns it has scored and how many knee operations its quarterback has had (not really on that last one, but you get the idea).

Anyway, whenever an ink-stained wretch is confused . . . whenever a sportscaster doesn't want to muss his spray-set hair by scratching his head in bewilderment -- when they don't know what it all means, they call Fran Connors, who we imagine sitting in a sterile cubicle, check-by-jowl with a computer, three calculators, an abacus and a prepaid ticket to Rio in case he fouls up.

"I've been pretty accurate," said Connors, 29, a former sports publicist at Georgetown who has been with the NFL two years. "There is," he said, trying to chuckle, "no margin for error. A couple times, I've awakened in the middle of night, wondering if I had the conference record right, the division record right, all the 'ifs' and 'whats.' Really."

With one weekend to go in this NFL season, nearly half the league teams -- 13 of the 28 -- still have the right to dream of reaching the Super Bowl. Seven of those teams already have qualified for the playoffs that begin Dec. 23. Six others are in contention for the remaining three playoff spots. d

The possibilities of such a tangle fascinated Connors so much that the NFL man, a mathematical masochist, set about figuring if there was any way the Philadelphia Eagles could win the National Conference's East Division.

The East champion is likely to be the winner of Sunday's Dallas-Washington game. But what if there is no winner? What if there is a tie? The thought must have come to Connors at 3 o'clock in the morning, bringing him bolt upright in bed. "The only way Philadelphia can win the East is if the Redskins and Cowboys tie," Connors said. "Since the NFL put in the overtime period the league has played 1,190 games -- and only three have ended in ties. So if you divide three by 1,190, you get .0025.

The Eagles have a .0025 chance." Wait. Not really. The Eagles have to win at Houston, and the probabilities there are . . .

A headache is coming on.

"Figuring out the possibilities has been a job of assimilation, correlation and collation," Connors said. "And while I do all that, my blood coagulates."