Quarter-miler Calvin Harrison likely lost his place on the U.S. Olympic team yesterday when he received a two-year ban for a second stimulant offense from the North American Court of Arbitration for Sport.

Harrison, selected for the pool of runners for the 4x400-meter relay in Athens, cannot compete again until July 25, 2006, unless the result is overturned through appeal to the Swiss-based Court of Arbitration for Sport. His lawyer, Edward G. Williams, said Harrison had not decided whether to appeal.

Appeals in such cases rarely have been granted.

Harrison likely will become the sixth U.S. track and field athlete recently charged with a drug offense to either fail to qualify for the team or to lose his right to compete. Only one other U.S. Olympian, Torri Edwards, still has a pending drug case.

Edwards, who qualified for Athens in the 100 and 200 meters, tested positive in April for a stimulant, but under new rules faces a two-year ban for a first offense.

Harrison, 30, tested positive last summer for modafinil, a prescription drug used to treat narcolepsy. Seven other U.S. athletes also tested positive for the same stimulant last year, but four of them received only public warnings because the violations were their first offenses. (The others also had steroid positives.)

Harrison received the two-year ban from a three-person arbitration panel under the rules of the U.S. Anti-Doping Agency because he tested positive in 1993 for pseudoephedrine, a stimulant found in common-cold medication that is no longer on the International Olympic Committee's banned list. The panel ruled that Harrison should surrender all results since the date of the offense, June 21, 2003.

"We were particularly disappointed that the arbitrators did not treat the 1993 offense as a nullity given the fact that pseudoephedrine is no longer on the 'list,' " Williams said in an e-mail.

The ruling jeopardizes the team gold medal Harrison helped the United States win at the 2003 world championships in the 4x400 relay. The world governing body of track and field (IAAF) could not be reached to comment yesterday.

The judgment demonstrated the hard-line approach USADA and the IAAF customarily have taken with positive tests. Harrison's first positive came at a junior meet when he was 19.

Harrison likely will surrender his spot in the relay pool to Kelly Willie, who finished seventh in the 400 at the U.S. trials, U.S. men's Olympic coach George Williams said just more than a week ago. However, Williams also could choose to replace him with a current member of the U.S. team.

This is the second time in recent weeks that Harrison has faced an Olympic-related setback. A member of the 4x400 team that won a gold medal at the 2000 Games, Harrison learned two weeks ago that he would have to relinquish that medal because of a 1999 positive test by relay teammate Jerome Young.

Harrison's twin brother, Alvin, faces a lifetime ban for drug violations from USADA. Alvin Harrison, who won the silver medal in the 400 in Sydney, did not qualify for this Olympic team.