Washington Redskin safety Tony Peters pleaded guilty in federal court in Alexandria yesterday to conspiracy to distribute $115,000 worth of cocaine and use of a telephone to set up a drug deal. Peters was immediately suspended without pay by the National Football League until he is sentenced Oct. 7.

NFL Commissioner Pete Rozelle's decision to suspend Peters means that he cannot play with the Redskins until the sixth game of the season, at St. Louis on Oct. 9. But sources close to the team have said they do not expect Peters to play at all this season.

Peters, who signed a $1 million, four-year contract with the Redskins last spring, faces up to 19 years in prison and fines of $55,000 in connection with the guilty pleas. An NFL spokesman said yesterday that the league will make a final decision on Peters' status after the sentencing.

"I was saddened to hear that he admitted his implication in the matter," Redskins owner Jack Kent Cooke said yesterday. "Knowing Tony as I do, I'm sure he will survive it. I know somehow he will overcome this adversity."

Redskins coach Joe Gibbs said he was not familiar with the details of Peters' guilty pleas but added, "I do hope that Tony can get everything ironed out."

During a 30-minute hearing at U.S. District Court in Alexandria, prosecutors said that in exchange for the guilty pleas, the government would drop seven other felony charges brought against Peters last month in connection with alleged sales of cocaine to undercover agents in Arlington and Canada.

Peters, dressed in designer blue jeans and a lavender, short-sleeve polo shirt, listened impassively as Assistant U.S. Attorney Joseph J. Aronica told the court that the 30-year-old defensive star introduced a drug supplier to undercover agents in June and was later paid $3,000 for setting up two sales.

Flanked by his defense lawyers, Peters answered "Yes, sir," when Judge Richard L. Williams asked if the government had accurately stated the evidence against him.

"Do you make any claims whatsoever that you are innocent of the charges as given . . . ?" Williams asked, specifically referring to conspiracy and misuse of a telephone.

"No, sir," Peters responded.

A key member of a defensive unit that figured prominently in the Redskins' Super Bowl victory last season, Peters went on leave with pay shortly after he was arrested at the Redskins training camp in Carlisle, Pa., the morning of Aug. 3. There was no hint during yesterday's hearing as to what may have motivated Peters to become involved in the drug conspiracy.

Peters, who had earlier pleaded innocent to all charges against him, remains free on his personal recognizance pending sentencing. Lon S. Babby, one of his attorneys, declined to comment after the hearing. A team source familiar with the case said it seems likely that Peters, who has no previous criminal record, will be incarcerated as a result of his guilty pleas, even if only for a short time.

Prosecutor Aronica said the plea agreement does not require Peters to cooperate with the government in developing evidence against seven other men named with him in an 18-count indictment returned Aug. 10. In response to a question in court from Williams, Peters said he would testify if he is called as a witness.

Peters is the only one of the eight to have pleaded guilty to any of the counts.

In addition to the conspiracy charge, Peters pleaded guilty to one count of illegal use of a telephone. That charge involved a July 29 phone call Peters made to an undercover agent in Fairfax from Carlisle to discuss payment for his role in one of the sales.

The conspiracy charge carries a maximum term of 15 years in prison and a $25,000 fine and a mandatory special probation period of at least three years. The telephone offense provides for up to four years' imprisonment and a $30,000 fine.

The charges against Peters dropped yesterday in return for the two guilty pleas were three counts of possession of cocaine with intent to distribute, three counts of distribution of the drug and one count of interstate travel to conduct illegal activities.

Peters is the fifth player the NFL has suspended this summer for involvement with cocaine. The other four are Pete Johnson and Ross Browner of the Cincinnati Bengals, E.J. Junior of the St. Louis Cardinals and Greg Stemrick of the New Orleans Saints.

Junior and Stemrick were arrested on separate cocaine felony charges and were placed on probation after pleading guilty or no contest. Browner and Johnson, both granted immunity from prosecution, testified in a federal drug case that they each had purchased cocaine on several occasions from a drug dealer.

Prosecutors alleged that the conspiracy involving Peters began in the fall of last year when a Canadian undercover agent bought a gram of cocaine as a sample from Toronto residents Charles Bray, Peters' half brother, and Bray's brother Douglas Bray, both of whom are named in the indictment. The Brays said the sample had been provided by Peters, the prosecution said.

On June 28 at the Key Bridge Marriott hotel, Peters allegedly introduced two undercover agents to another defendant, Maryland resident Ronald Kirby Wood, a grand jury indictment in the case said. The four men went to a Georgetown restaurant where sale of the drug was discussed, according to the indictment.

Wood and other defendants later made two cocaine sales to undercover agents, after which an agent paid Peters $3,000 for helping set up the sales, the indictment alleged.

A third sale, consisting of 2.5 pounds of cocaine, took place Aug. 2 at the Hospitality House Motor Inn in Crystal City, the indictment said. After that, Peters and six of the other men were arrested. The eighth man named in the indictment, Jose Cebada of New York, has not been apprehended.

At yesterday's court hearing, Aronica said that Wood and an undercover agent also had discussed the sale of six pounds of cocaine but Wood expressed doubt that he could provide that quantity of the drug. Aronica said in court that Peters later told an agent he had called someone in Oklahoma to try to line up new sources of the drug.

If Peters had been convicted of all nine charges against him, he would have faced up to 114 years in jail and $215,000 in fines.