The Court of Arbitration for Sport announced that it had cut Serbian tennis player Viktor Troicki`s 18-month doping ban to 12 months.
The Swiss-based tribunal said that while its appeals panel had rejected the former world number 12`s call to void the sanction, it ruled that there was no indication that he had sought to get away with doping.
"The CAS has determined that the player had committed a doping offence, but that his fault was not significant," it said in a statement.
Troicki, a Davis Cup winner in 2010, turned to the CAS in August in a drive to overturn his ban which was handed down by the International Tennis Federation (ITF).
The sanction, imposed in July came after he was found guilty of failing to provide a blood sample during a drugs test at the Monte Carlo Masters.
However despite the reduction in the ban, Troicki will now play no part in Serbia`s attempt to regain the Davis Cup from the Czech Republic which begins on November 15.
The 27-year-old maintained that anti-doping officials at the tournament had told him his urine sample was sufficient, given that he did not feel well enough to provide a blood sample.
But that failure constituted a dope test infringement, said the ITF, despite the player`s insistence that he was under stress at the time.
The CAS said that the anti-doping control officer, or DCO, on duty at the Masters "should have informed the player in clearer terms of the risks caused by his refusal to undergo a blood test".
"Despite the misunderstanding between the player and the DCO, there was no suggestion that Mr. Troicki intended to evade the detection of a banned substance in his system," it added.
Troicki`s closed-door appeal was heard by a three-member panel of CAS arbitrators from Canada, Italy and Britain at the tribunal`s Lausanne headquarters on October 9.
As a result of their decision to cut the 18-month ban to the minimum 12 months allowed by the rules, Troicki will be able to return to the circuit next July, the CAS said.