In the quietude of the fifth round of the National Football League draft -- the No. 114th pick, to be precise -- the Dallas Cowboys selected running back Herschel Walker.

"It's a gamble worth taking," says Gil Brandt, the Cowboys' vice president for personnel. "It may never bear fruit. But it also could be the steal of the draft."

Selecting Walker Tuesday was a gamble because the former Heisman Trophy-winning running back from the University of Georgia is under contract with the New Jersey Generals of the U.S. Football League.

According to the Generals' owner, Donald Trump, Walker is signed through the 1988 season.

However, the drafting of Walker is what is known in NFL circles as a speculative pick. This one just happens to carry thunderous possibilities. Can you imagine a backfield with both Tony Dorsett and Walker?

"If the USFL goes under or if the New Jersey Generals go under or if Donald Trump sells the team, Herschel's a free agent," said Peter Johnson of the International Management Group, which is Walker's agent. "He would be free to negotiate with the Cowboys immediately. Donald is obligated to pay him all four years (of his current contract) regardless.

"The only payment the Cowboys would have to make would be Herschel's salary."

Many now question the USFL's staying power. Franchises in Los Angeles, Birmingham and Houston are having severe financial problems. Although the USFL voted on Monday to move from the spring to a fall schedule in 1986, there still is no television contract from one of the three major networks.

Owner John Bassett, whose Tampa Bay Bandits have been unarguably the USFL's most stable franchise in the league's three years, was angered by the proposed move to the fall. He says that, after this season, he will withdraw his team from the USFL and start his own spring league.

Herein lies the speculation. The Cowboys' drafting Walker in 1985 is the same as the Redskins' drafting running back Kelvin Bryant from North Carolina in 1983.

If the USFL should fold, players such as Walker and the Baltimore Stars' Bryant could become available.

Dallas will retain Walker's NFL rights for four years, then will hold a right to match any NFL team's potential offer when he becomes a free agent after May 1, 1989, according to NFL spokesman Joe Browne. (The Redskins will retain exclusive NFL rights to Bryant for two more years, then will assume a right of first refusal.)

Trump looks at the drafting of Walker differently.

"I think it's the greatest compliment to the USFL that you can have," he said yesterday. "Herschel, as the NFL has stated again and again, would be the No. 1 pick in the draft of the century.

"But for the NFL to wait five rounds to draft him, they know that we (the USFL) are not going anywhere. If they had drafted him in the first round, that would tell you that they thought differently. They are smart people."

The USFL is proceeding with a $1.32 billion antitrust suit to enjoin the NFL from appearing on all three major television networks. For this and other reasons, NFL employes don't speak openly about the USFL.

Asked if the Cowboys selected Walker because they expect the USFL soon might disappear, Brandt said, "I don't have any better feeling on that than anyone else in the country. We would have made the same choice if Herschel had been playing in Canada . . . When you get to the fifth round and you have an extra pick, one we obtained in the Butch Johnson trade (with Houston), it's a good gamble."

This was the first NFL draft in which Walker was eligible. League rules specify that a player becomes eligible to be drafted when he has graduated, or when he has used all four years of his college eligibility, unless five years have lapsed since he was a freshman.

Walker is only 23 years old. Had he remained at Georgia, where he rushed for 5,259 yards in three seasons, he almost certainly would have become the NFL's No. 1 selection last year.

However, he signed with the Generals after his junior year for a reported three years and $5 million. Then in March 1984, his contract was extended through 1988 and reportedly netted him $6 million. That's $1.25 million per season.

He rushed for 1,812 yards in his rookie USFL season, then 1,339 last season. After offseason shoulder surgery, he has returned this season to rush for 1,163 yards, including a record-setting 233 yards in a 31-25 victory over Houston on April 7.

Some football scouts wondered late last season and early in this USFL season if his football heart hadn't begun skipping a beat or two.

"I wondered if making a lot of money didn't diminish his competitiveness," Brandt admitted. "But I didn't know about his shoulder injury.

"These last four or five weeks, he's played like the Herschel Walker who played against Penn State for the national championship (in 1983), running against 10- and 11-man fronts."

Walker was unavailable to comment yesterday. After being drafted by the Cowboys, though, Trump's Generals released a statement quoting Walker as saying, "I'm very flattered and very honored to be picked by the Dallas Cowboys. By the same aspect, my focus is on the New Jersey Generals and winning a championship for the Generals in the United States Football League."

Speculation draft picks are nothing new to the Cowboys. Twenty-one years ago, they selected quarterback Roger Staubach -- also a Heisman Trophy winner -- even though he had another season at the Naval Academy and then a four-year military commitment.

It paid off. In 1969, five years after he was drafted by the Cowboys, he began an 11-year career that included stopoffs at four Super Bowls and a finish line in the Pro Football Hall of Fame.

If Walker fulfilled his contract with the Generals and then, hypothetically speaking, signed with Dallas for the 1989 season, he would be 27, with six years experience testing pro defenses.

Brandt made his point when he said he wouldn't mind such a scenario. "John Riggins is still playing quite well," he said, "and I don't think anybody is quite sure how old he is."