Coming up to the opening of the National Football League season, Dan Pastorini's passing arm is improved and he is expected to start for the Houston Oilers against the Redskins in Washington Sunday.

While Redskin quarterback Joe Theismann is more a key part of the team's offense than Pastorini is of his, the Redskins lack a quality passing attack. Houston by 4.

In other openers:

New York Giants at Philadelphia -- The Giants lost left tackle Gordon King, giving a solid edge to the Eagle defense, whose Carl Hairston is sure to keep the pressure on quarterback Joe Pisarcik. Eagle quarterback Ron Jaworski is worth a touchdown difference here. Philadelpia by 7.

Dallas at St. Louis -- St. Louis' main strength is the passing game. The Cowboy offense, even without runner Tony Dorsett, still is the best in the NFC East. Roger Staubach gets an edge over St. Louis' Jim Hart at quarterback. Dallas by 4.

Green Bay at Chicago -- The Bears quarterback picture still is unclear. The Packer running game is much improved with the addition of Eddie Lee Ivery. Bears by 3.

Baltimore at Kansas City -- The Colts start a healthy Bert Jones at quarterback with explosive Joe Washington in the backfield, Kansas City's defense against the run is much better than last year. Mike Livingston starts at quarterback after the finest preseason of his career. Kansas City by 2.

Oakland at Los Angeles -- The Rams enjoyed a fine preseason, Oakland's big-play offense is back in gear with quarterback Ken Stabler in great shape. The club's defense is improved but its secondary is vulnerable to the deep passing attack. Los Angeles by 3.

Cincinnati at Denver -- the Bengals are greatly improved over a year ago as draft picks Charles Alexander and Dan Ross hype an offense led by quarterback Ken Anderson, who enjoyed one of his finest summers ever. Denver by 4.

Pittsburgh at New England (Monday) -- The Steelers are the strongest club in the league and Terry Bradshaw is the top quarterback in football. The Patriots are another talent-rich club. Steve Grogan handles a top-rate Patriot offense and the most productive running game in the NFL. The Steelers by 2.

In other games: Tampa Bay by 4 over Detroit on Saturday, Minnesota by 8 over San Francisco, Miami by 5 over Buffalo, New Orleans by 4 over Atlanta, Seattle by 1 over San Diego and the Jets by 3 over Cleveland on Sunday.