For pro football fans who prefer the comfort of an easy chair and a television set to the cold of Fenway Park in December, the biggest weekend of the year is coming up. On Saturday and Sunday of this week two league championships will be decided, and Boston area residents can see both on TV.

The Hub's own Patriots, who forged ahead in the Eastern Division of the American Football League by clobbering Houston Sunday, can clinch the title Saturday by beating or tying Kansas City (channel 7, 3:30 p.m.).

On paper, it's easy. The Patriots have won seven games, lost five and tied one, while the Chiefs have collapsed to a 3-7-2 mark.

But a Boston victory is far from inevitable. The same Chiefs who now are straggling home third in the Western Division were the league champs last year when they played as the Dallas Texans. Last Sunday, after going winless for two months, the Chiefs exploded against Denver for a 52-21 win. Saturday's should be a good, close ball game.

On Sunday the New York Giants play off with the Pittsburgh Steelers for the Eastern Division title in the National Football League (channel 5, 2 p.m.). A win or a tie will make the Giants champions, but if the Steelers beat them again--and they pasted the defending champs 31-0 in September--the Giants is dead.

There was a bit of the fluke about the Steelers' win last time. Y.A. Tittle, the Giants' masterful passer, was on the bench with injuries. His replacement, Ralph Guglielmi, showed such brilliance in the Steelers game that the Giants displayed their gratitude by promptly trading him to San Francisco.

By the way, Green Bay plays Los Angeles Saturday, and that's on TV, too (channel 5,4 p.m.). If the Packers win and the Chicago Bears lose on Sunday, Green Bay wins the N.F.L. Western Division.