Kim McQuilken sat on a pine folding chair, hunched over and in pain. He was filthy. Even his ordinarily tawny hair was deep ocher. His cleats were clotted with the mud from day's freezing rain and he could not move without a grimace, could not talk above a hoarse whisper.

But he could not remember, as an adult, having had a more fulfilling Sunday afternoon than last week. At the end of that 22-16 overtime victory against Michigan, McQuilken lay prostrate in the mud after he had released the winning touchdown pass to Joey Walters.

It was a victory over perhaps the worst team in a fledgling league, a victory plagued with mistakes played out before a stadium not so much filled as speckled with spectators. But within its own particular boundaries and its own particular set of circumstances, the game was a joy to its victors.

"It just doesn't get much better than that," McQuilken said. "There's even something that's sadistically satisfying when you get nailed after throwing it. It's as if you really earned it."

Three weeks before, in a similar downpour, the 31-year-old quarterback also viewed the black heavens from flat on his back. No pennies from heaven that day, only harsh rain and telling statistics.

Coach Ray Jauch jerked McQuilken after 14 plays in the season opener against Chicago. "You have to make a decision whether you're moving the football and putting points on the board," Jauch said. McQuilken had completed two of seven passes and had fumbled twice. The offense was going nowhere.

This was not why McQuilken ended his retirement from professional football. After four years with Atlanta and three with the Redskins--all as a backup--he had signed a contract to play. But even in the U.S. Football League, with its hodgepodge of quality, there is always someone on the bench.

Mike Hohensee, a rookie from Minnesota with a decidedly stronger arm, replaced McQuilken against the Blitz and showed more poise and promise.

From the moment the Federals signed Hohensee in training camp, Jauch indicated he would use two quarterbacks. Hohensee started Washington's second game, against Los Angeles, but he left the field in the second period with a fractured sternum. He is not expected to play again until the April 11 Monday night's game against the Arizona Wranglers.

That left McQuilken.

Aided by the arrival of two first-class receivers, Mike Holmes and Walters, his short- and medium-range passes improved. His confidence in the huddle was now matched with poise in the pocket.

Against Boston, McQuilken was 25 of 47 for 322 yards and one touchdown, although he had four interceptions. The following week, against Michigan, he was 24 of 48 for 324 yards, three touchdowns and one interception.

Against Philadelphia Sunday, McQuilken and the Federals will be hard pressed to win. Nevertheless, he relishes the pressure, the knowledge that he will go the whole way until Hohensee returns.

When Hohensee does return, however, Jauch said, "We'll be back in the same situation. I think there'll be room for both quarterbacks to play."

McQuilken, for his part, can hardly afford to look ahead. "I can't worry past this week. Eighteen games is a long season. I'd feel sorry for this team if it had only one quarterback."

The team activated linebacker Dan Lloyd and wide receiver Mike Harris and placed wide receiver Jeff Postell and running back Mark Sanford on the developmental squad. graphics/photo: Federals quarterback Kim McQuilken