Friends of former Dallas wide receiver Bob Hayes, who pleaded guilty in a Dallas court this week to trafficking in cocaine, said Hayes could never totally accept the fact that his football career was over.

The 35-year-old Olympic gold medalist pleaded guilty Wednesday to charges that he supplied cocaine and methaqualone to an under-cover policeman. The policeman said Hayes told him be began using drugs while playing for the Cowboys.

Hayes faces a maximum of life in prison on the cocaine charges and a maximum 10 years imprisonment on the methaqualone charge.

Hayes got the judge to delay sentencing for a week while his attorneys round up character witnesses to bolster his plea for leniency.

Until sentencing, Hayes will remain free on $30,000 bond set following his arrest last April 6.

Hayes achieved acclaim as the fastest human when he won two gold medals in the sprints in the 1964 Olympics in Tokyo.

Then he turned to football with the Dallas Cowboys and was an AllPro selection in 1966. His salary was estimated to be $90,000. He was selected to play in the Pro Bowl three times, played in four championship games and set Cowboy records that still stand for in scoring (75 touchdowns), receiving (358 catches for 7,177 yards) and punt returns (102 for 1,147 yards), although he had not returned a punt since 1971. But he became unhappy in 1974 when his playing time was reduced.

He told interviewers he was not being given a fair chance by the Cowboys and asked to be traded.

He was dealt to the San Francisco 49ers for a high draft choice in July 1975 and was determined to "show them (the Cowboys)" he could still play regularly.

The 49ers later dropped him.

Even though he was not as fast as he had been, and had trouble holding onto the ball in his later years, Hayes believed he could still play in the NFL. Friends say his final year with the Cowboys and short stint with the 49ers left him discouraged, if not completely bitter.

Hayes went into the wig business for a while. He also was associated with former Cowboy-turned-author Pete Gent in a printing firm. More recently he was an executive in a computer business. Shortly before he pleaded guilty to Wednesday to supplying cocaine and methaqualone, pills more commonly known as Quaaludes, to the undercover policeman in the Dallas suburb of Addison, Hayes told friends he expected to head a summer track and field program under the sponsorship of a soft drink firm.

The city of Dallas and longtime Cowboy teammates were shocked by his testimony that he used drugs while playing.

Offensive tackle Rayfield Wright used to ride to Cowboy practices with Hayes and said he had no reason to believe Hayes was ever involved in drugs. Trainer Don Cochren made a similar observation.

Defensive tackle Jethro Pugh, who came up as a rookie with Hayes, said he was "perplexed. I know Bob Hayes is no criminal."

Cornell Green, who recently resigned as a Cowboy scout, noted that he had spent a lot of time as a former player "on the field, off the field and socially" with Hayes and "never noticed anything to suggest he was using dope."

A reporter who regularly covers the Cowboys said, "I can't find anyone who can accept the idea that Hayes was on dope when he was still playing."

Hayes' attorney, Mike Gibson, said yesterday he has asked Cowboy General Manager Tex Schramm and Coach Tom Landry to appear at a hearing Thursday in behalf of Hayes' plea for leniency, but didn't know whether they would.

Landry, attending a National Football League meeting in Hawaii, could not be reached for comment. Schramm said he had not yet been asked to testify but that that his first inclination was, "Yes, I would appear on his behalf. I have lots of friendship and respect for Bob for the years he spent with the Cowboys and I would do anything I could to help him."

Green, Pugh, Wright and other former teammates are expected to be character witnesses.

Hayes, convicted in 1966 in Florida of robbery but pardoned by the governor at the time, has waived a jury trial since Texas law permits only judges to order a probated sentence for someone with a previous probation or sentence.

The judge will determine what sentence to impose after hearing recommendations from the defense and the state Thursday.

Dennis Kelly, a Braniff airlines pilot, testified that he met Hayes in early 1978 through a secretary employed at Dycon International Inc., a Dallas-based computer firm of which Hayes is a vice president. Hayes knew Kelly was a pilot. He did not know Kelly was a part-time undercover police officer in Addison.

Kelly testified that during a double date with Hayes and the latter's wife in February 1978 that drugs were discussed. Kelly said Hayes told him he could get any kind of drug Kelly might want.

Kelly told the court he purchased three grams of cocaine from Hayes on March 9 that year, two grams of cocaine 20 days later and three methaqualone pills two days after that.

A canceled check for $300, used to pay for the three grams of cocaine, was offered in evidence.

Kelly also introduced and played before District Judge Richard Mays 12 tape recordings which, Kelly testified, were made of his conversations with Hayes that March.

There has been speculation in Dallas that the taped conversations and the investigation of Hayes went on so long because police were hoping to seize more important figures in a drug operation.