World 100-meter champion Christian Coleman had his two-year ban for breaching anti-doping whereabouts rules reduced to 18 months by the Court of Arbitration for Sport (CAS) on Friday but he will still be ineligible for the Tokyo Olympics this summer.

Coleman's ban, which was due to run until May 13, 2022, will now end on this year's November 14, meaning he will miss the July 23-August 8 Tokyo Games but he can return to competition in time to defend his world indoor and outdoor titles at world championships next year.

The 25-year-old American sprinter had been handed a two-year suspension by an independent tribunal of track and field's Athletics Integrity Unit (AIU) in October last year.

He appealed against his ban in November.

"Christian Coleman's appeal was partially upheld and he will serve a reduced period of ineligibility of 18 months as from May 14, 2020," CAS said in a statement on Friday.

CAS said its panel had determined Coleman had committed an anti-doping violation but found his "degree of negligence to be lower than that established in the challenged decision".

The fact of three failures in a 12-month period to be at a location provided to anti-doping officials is considered a doping violation.

Coleman, who won the 100-meter world title at the 2019 Doha world championships in 9.76 seconds and had been the hot favorite for Olympic gold in Tokyo, said he was disappointed that he would miss the Summer Games.

"While I appreciate that the arbitrators correctly found that I am a clean athlete, I am obviously disappointed that I will miss the Olympic Games this summer," said Coleman in a statement to Reuters.

He said he would now focus on next year's world championships, which will be staged in the United States for the first time.

"I look forward to representing the United States at both world championships in 2022, especially the first ever world championships held in the United States next summer where I plan to defend my world title against a new Olympic champion in the 100 meters."