In a stunning move that further shakes up the revamped NFC East, the Dallas Cowboys abruptly released their incumbent starting quarterback, Quincy Carter, yesterday after, a source said, he failed a recent drug test. Cowboys Coach Bill Parcells said he plans to enter the season with 40-year-old Vinny Testaverde as his starter.

Cowboys officials declined to specify the reasons for the move, but an NFL source, speaking on the condition of anonymity because drug test results are confidential as per league policy, confirmed reports that Carter failed a drug test and was in the league's substance-abuse program because of a previous failed test.

"I'm shocked. I'm at a loss for words," Carter told the Dallas Morning News. "The one thing I know and the people who have been around me all my life know is that cocaine has never been an issue for me. It never will be. And it's disturbing that a rumor like that would come out. I have not one bad thing to say about the Dallas Cowboys, Bill Parcells or [owner] Jerry Jones. I have a lot of friends on that team. I just want my teammates and fans to know that cocaine rumor is ridiculous."

Carter, 26, helped the Cowboys to 10 regular season wins and a playoff appearance last season in Parcells's first season as the team's coach. But he was only the NFC's 11th-rated passer, and the Cowboys looked to upgrade the position in the offseason, trading for promising rookie Drew Henson and signing Testaverde as a free agent in June after he was released by the New York Jets.

The Cowboys likely will enter the season with Testaverde as their starter and Henson, who never has played an NFL game, as his backup.

"We've made a decision to move in a different direction," Cowboys owner Jerry Jones said at the club's training camp in Oxnard, Calif. "We're not going to get into a lot of details about the process that led to this decision, but this was not a difficult decision at all. It is, though, very disappointing."

Said Parcells: "I just couldn't keep him in the plans. . . . I'm saddened by this because I've got 18 months invested here, too. I've got two offseason programs and a regular season and a playoff game invested in this program, too. . . . [But] I am in total agreement with what we're doing. We just couldn't continue to have him in our plans.

"I told the players we're in a replacement business here. I replaced somebody. Jerry replaced somebody. They replaced somebody, and somebody is going to replace all of us. I learned that a long time ago."

It was unclear last night who administered the drug test that Carter failed. The possibility, mentioned in published reports, that the test was conducted by the team, and not the league, drew the ire of union head Gene Upshaw.

"I just heard about this," Upshaw said. "I won't comment on a drug case. I will say under our collective bargaining agreement a club cannot conduct its own, independent drug testing and impose its own discipline. They just can't do it."

Officials from both the league and the Cowboys said that the team does not administer drug tests.

Carter is not under an NFL-mandated suspension, the source said. Under the league's substance abuse program, it takes a third positive test to bring a four-game suspension. Parcells said that, as far as he knew, Carter was free to sign with another team.

Said Jones: "We should just leave it at it just was not a difficult decision, and not get into a definition of what it was about. . . . This decision, we would not have made it if it was not in the best interests of everybody involved. Rest assured, it was not difficult. . . . Quincy did some really good things with the Dallas Cowboys. Quincy has many fine qualities. [But] there are some things, some imperfections, that don't fit with a team concept. . . . This is our policy, the team's policy, Bill's policy. This is what we're all about."

No Parcells-coached team has failed to improve by fewer than three victories in his second season with the club, but now he must try to overcome his quarterback troubles to win in a strengthened division.

Testaverde had his best season playing for Parcells with the Jets in 1998. He had a passer rating of 90.6 last season -- which would have placed him fifth in the AFC if he'd had enough attempts to quality for the official rankings -- while filling in for injured Jets starter Chad Pennington. But he will turn 41 in November and hasn't been a regular NFL starter since 2001.

"Right now, that's the most experienced player I have, and I'm confident in that player," Parcells said. "We're going to have to alter some things in terms of strategy. . . . I'm confident in the players we have. I just have to coach them."