Dallas Cowboys Coach Tom Landry may need to replace his snappy fedora with an asbestos helmet, considering all the heat he's taking. But Landry certainly doesn't deserve the sole blame for years and years of poor drafting that, as much as anything, has contributed to the team's demise.

Of the nine first-round draft choices the Cowboys have had since Tony Dorsett in 1977, only two are starting (defensive ends Jim Jeffcoat and Kevin Brooks). Even projecting 1987 pick Danny Noonan into a starting spot next year makes it only three of nine.

Receiver Mike Sherrard (1986) has missed the season with a broken leg. Linebacker Billy Cannon Jr. (1984) played only eight games before retiring with a neck injury. Receiver Rod Hill (1982) was traded after two seasons. Tackle Howard Richards (1981) was cut before this season. Center Robert Shaw (1979) had to quit after three seasons because of a knee injury. Larry Bethea (1978) committed drug-related suicide. So it's not like Landry has future Hall-of-Famers lounging around the locker room.

By contrast, look at the last two Super Bowl champions. Of the Giants' last nine No. 1 picks, eight have started this season. Of the Bears' last 10 No. 1 picks, all 10 start . . .

Then, there's the matter of quarterbacks. Since Dallas last picked a quarterback in the first round (1965, Craig Morton), every team in the NFL has drafted a quarterback in the first round except Seattle (which never has taken a quarterback in the first round) and the Redskins (1961, Norm Snead).

All the evidence in recent years points to a team needing a top-flight quarterback to get into the Super Bowl. Of the last six teams to make the Super Bowl (the Giants and Broncos, Bears and Patriots, 49ers and Dolphins), five had quarterbacks drafted in the first round, the exception being San Francisco's Joe Montana (third-round pick in 1979).

The Cowboys started the season with the oldest starting running back in the league (Tony Dorsett, 33), one of the oldest quarterbacks (Danny White, 35) and an old defensive line (Randy White, 34; Ed Jones, 36; John Dutton, 36). Two replacement players start on offense. All things considered, it's a wonder the Cowboys have won five games. Seahawks' Highs and Lows

Proof of the theory that Seattle is the most schizophrenic team in the league: Six of its eight games since the players' strike ended have been decided by 10 or more points. The Seahawks have won four games by an average margin of 19 points, but have lost two games by an average of 15 . . . The NFL is offering evidence that this season's games are more competitive than ever. Including 12 overtime games, 50 percent of the games this season have been decided by seven points or fewer, the highest percentage since the NFL began keeping that statistic in 1970. In addition, the winning team has had to come from behind in the fourth quarter nearly 25 percent of the time . . .

Speaking of comebacks, since taking over for Joe Theismann in late 1985, Redskins quarterback Jay Schroeder has led his team to victory nine times in 16 games after trailing in the fourth quarter . . . Los Angeles Rams running back Charles White, who rushed for a total of 1,378 yards in six NFL seasons, has gained 1,054 this year, primarily because of the opportunity created by the departure of Eric Dickerson to the Colts . . .

Another Los Angeles running back, Bo Jackson, will find himself playing a road game at home because his Raiders meet the Chiefs in Jackson's summer home of Kansas City on Sunday. George Brett, a Kansas City Royals teammate, plans to travel from L.A. to K.C. to watch Jackson play and perhaps lend a little support, if needed. "The fans {in Kansas City}, when he said he wanted to play football, they really turned on him," said Brett, who has been attending Raiders home games to watch Jackson. "I don't think it was fair. I hope he has a great game against the Chiefs; maybe it'll change their opinion of him. It made life real tough on Bo Jackson; I know that for sure."

With 172 rushing yards against Buffalo Sunday, Dickerson would do something Jim Brown, Earl Campbell, Walter Payton, O.J. Simpson and Tony Dorsett couldn't: reach 8,000 yards in 71 games. That's nine games earlier than Brown, 12 earlier than Campbell, 15 earlier than Payton. 'He Won't Get In'

Former Bears great Gale Sayers, who wrote his master's thesis on, "The White Power Structure in Pro Football" at the University of Kansas, is more than skeptical about Walter Payton's goal of owning a pro franchise anytime soon. "I'm telling you," Sayers said, "he won't get in. Believe me. It's a closed society." . . .

The Upset Pick: The UP had a respectable week, with Pittsburgh coming through against Seattle and Kansas City taking the favored Bengals to overtime, but the record still stands at 3-10. This week: The feisty Cowboys, 10-point underdogs, are in a shambles, but a victory here would make their season, so they'll beat the Redskins. And Buffalo will make a tight division tighter by going into Indianapolis and beating the Colts.