Seahawks in playoff debut; Packers fire Starr; dilemma for Sims

''I can't think of any profession as insecure as being a head coach in the National Football League. Your fate is never in your own hands. One injury to a key player, one bad call, one imperfect bounce and you can lose a whole year's work. Although they say the breaks even out over an extended period of time, most of us don't last long enough to prove it.''

Those quotes belong to Seattle's Chuck Knox, who has the 9-7 Seahawks in the NFL playoffs for the first time in their eight-year history. Knox was hired by Seattle last January after five winning seasons with the Los Angeles Rams, plus five more productive ones with the Buffalo Bills.

What Chuck inherited in Seattle was a team that won only four games during last year's strike-abbreviated season. The Seahawks had trouble stopping the run or mounting any kind of a consistent pass rush, while on offense they tied with the Baltimore Colts for fewest points scored in their 14-team conference.

However, Knox managed to solve most of his problems by giving the team a new 3-4 look on defense; trading for several veteran players who could improve his offensive line; and drafting running back Curt Warner of Penn State. Warner had a spectacular rookie season, gaining 1,449 yards to wind up as the AFC's rushing leader.

Knox says he has always divided his players into three distinct categories - Can Do; Can't Do; and Question Marks.

''A Can Do player requires very little coaching,'' Chuck explained. ''He's a natural - so good that you're really not going to improve him, because instincts are something that can't be coached.

''Can't Do players lack the great physical skills necessary to play pro football. Coaching will improve them. But basically you can push them only so far before the law of diminishing returns takes over and you have to drop them.

''Question Mark players often have the physical skills, but for some reason aren't getting the job done. Maybe the problem is psychological. Maybe it's motivation. But if you are going to put together a winning football team, you have to get the player out of the Question Mark category and into the Can Do section. And the quicker you are able to do this, the quicker your team will become a contender.'' Starr, Studley out; Sims's two contracts

Bart Starr was sacked as head coach of Green Bay primarily because the Packers have made the NFL playoffs only once (1982) since Starr succeeded Dan Devine as field boss in 1974. Bart's record after nine seasons with the Packers was an unimpressive 52-76-3, including this year's 8-8 mark. . . . Meanwhile interim Head Coach Chuck Studley of the Houston Oilers has resigned after learning from club officials that he is not being considered as a serious candidate for next season. During Studley's brief 10-game reign, the Oilers were 2-8. . . . The fact that the St. Louis Cardinals finished the regular season 8-7 -1, after starting 1-5, probably saved the job of Head Coach Jim Hanifan. Part of the Cardinals' turnaround began when Hanifan added more motion to his offense. However, there is still the matter of why St. Louis was outscored 152- 55 in its four losses to division rivals Washington and Dallas. . . .

Billy Sims, one of football's best running backs, has admitted signing two five-year contracts - one on July 1 with the USFL Houston Gamblers and a second on Dec. 17 with the NFL Detroit Lions, his present team, setting up a probable court battle to determine where he will play next year. Sims claims the clubs gave him signing bonuses of $1 million each. . . . Quarterback Brian Sipe of the Cleveland Browns, whose contract expires at the end of this season, has refused to comment on reports that he will sign a multi-year pact with the USFL New Jersey Generals. Sipe threw four touchdown passes Sunday in a 30-17 win over the Pittsburgh Steelers. . . . Wide receiver Calvin Muhammad of the Los Angeles Raiders, who majored in music at Texas Southern, owns three pianos, four guitars , a trumpet, a trombone, and a set of drums. Calvin wants to cut a record where he is the only musician. . . . If the Washington Redskins and the Dallas Cowboys meet again in the playoffs, a strong possibility, look for Dallas Coach Tom Landry to install a moving pocket for quarterback Danny White. The idea isn't so much to help White as it is to get the Redskins out of their regular defensive sets and create more outside running room for Tony Dorsett.

National Football League final standings

American Conference

East W L T Pct. c-Miami 12 4 0 .750 Buffalo 8 8 0 .500 New England 8 8 0 .500 N.Y. Jets 7 9 0 .438 Baltimore 7 9 0 .438 Central c-Pittsburgh 10 6 0 .625 Cleveland 9 7 0 .563 Cincinnati 7 9 0 .438 Houston 2 14 0 .125 West c-L.A. Raiders 12 4 0 .750 w-Denver 9 7 0 .563 w-Seattle 9 7 0 .563 San Diego 6 10 0 .375 Kansas City 6 10 0 .375

National Conference East W L T Pct. c-Washington 14 2 0 .875 w-Dallas 12 4 0 .750 St. Louis 8 7 1 .531 Philadelphia 5 11 0 .313 N.Y. Giants 3 12 1 .219 Central c-Detroit 9 7 0 .563 Green Bay 8 8 0 .500 Minnesota 8 8 0 .500 Chicago 8 8 0 .500 Tampa Bay 2 14 0 .125 West c-S.F. 10 6 0 .625 w-L.A. Rams 9 7 0 .563 New Orleans 8 8 0 .500 Atlanta 7 9 0 .438 c-division champion w-wild card playoff entrant

Playoffs (wild card round) Saturday's game (Dec. 24) Denver at Seattle, 4 p.m. (EST) Monday's game (Dec. 26) L.A. Rams at Dallas, 2:30 p.m. (EST)