The New Orleans Saints, seemingly ready to mortgage a piece of their future to save this season, yesterday traded three high draft picks for the Dallas Cowboys' backup quarterback, Steve Walsh.

Cowboys owner Jerry Jones said his team will receive the Saints' No. 1 and No. 3 choices in 1991 and a No. 2 pick in 1992. He said the No. 2 pick could be upgraded to a No. 1 if Walsh performs well for New Orleans. Dallas now has 10 picks in the first two rounds of the next two drafts, including five No. 1 selections.

Walsh, who started five games last season when Troy Aikman was injured, will compete for the starting job with John Fourcade, who has been erratic in the first three games.

"I'm excited. I'm ready to go to work. It feels like draft day all over again," Walsh said last night at a news conference at the Saints' training facility. "I'm happy and excited. I have a great opportunity and chance to make my career."

Cowboys Coach Jimmy Johnson said he and Jones debated until late Monday night whether to trade Walsh. But, Johnson said, Aikman "is the best quarterback in the NFL, as far as I'm concerned, and will be the best for the long haul."

For the Saints, it is a move to try to salvage the 1990 season, as well as solve their long-term quarterback problem. New Orleans is 1-2, and before Sunday's 28-7 win over Phoenix it had not scored a touchdown.

Fourcade entered last week's game as the league's lowest-rated quarterback. His backup was aging Tommy Kramer, who was cut to make room for Walsh. Bobby Hebert, the starter the past several years, has been a holdout and has said he will not play for the Saints again.

"I hope he doesn't think he's just going to come in and get the job because I have something to say about that," Fourcade said. " . . . Basically, Steve Walsh is coming in here with just his college statistics. Sure he won a national championship, but this isn't college and these aren't the Miami Hurricanes."

Coach Jim Mora said Fourcade will remain No. 1 for now and that his staff will start working with Walsh today. Walsh will work with the team when it returns Friday from three days off. The Saints and the rest of the NFC West have Sunday off.

"We haven't gotten the play at quarterback we'd like, and yet it's been getting better. We saw an opportunity to go out and get a good young quarterback and we did it," Mora said, adding Walsh could be ready when New Orleans resumes against Atlanta on Oct. 7.

The Los Angeles Rams play the Saints twice in the last four weeks of the season. Jack Faulkner, adminstrator of football operations for the Rams, thinks they made a good deal.

"What this trade has done for New Orleans is help them immensely," he said. "They already have a real fine defense and they have a good running game. It gives them a quarterback, but it will take him a while to learn the system. He hasn't played very much and there is no one who said he can play in the NFL. The only thing he has done so far is to be drafted number one" -- in the 1989 supplemental draft.

Walsh, who led Miami to the national championship in 1987, completed 110 of 219 passes for 1,371 yards last season. He threw five touchdown passes and nine interceptions. This season Walsh is four of nine for 40 yards.

The deal gives the Cowboys three first-round picks next year -- their own, New Orleans's and Minnesota's, obtained last year in the Herschel Walker trade. However, taking Walsh in the supplemental draft cost Dallas what would have been the No. 1 overall pick in the last regular draft.