LAUSANNE, Switzerland -- Serbian tennis player Viktor Troicki's ban for avoiding a blood doping test was reduced from 18 months to one year on Tuesday, meaning he cannot play in the Davis Cup final next week.

The Court of Arbitration for Sport ordered him to serve a 12-month ban for skipping a blood test after losing at the Monte Carlo Masters in April. He blamed a tournament anti-doping officer who he claimed advised him to write to the ITF explaining that he was ill and could not give a blood sample. He had already given a urine sample, which later tested negative.

The 27-year-old Troicki said in a statement the ruling "puts an end to my dreams of being a top player. I worked my entire life for it, and it has been taken away from me in one afternoon by a doctor I didn't know."

His ranking peaked at No. 12 in June 2011. It fell from No. 53 to 77 since he was suspended by an International Tennis Federation tribunal in July.

"The player committed a doping offense, but his fault was not significant," the court said in a statement.

Troicki will be cleared to play again on July 15, having missed four Grand Slam events while suspended.

Serbia plays the Czech Republic in the Davis Cup final in Belgrade next week. Troicki appeared in the first two rounds this year. CAS fast-tracked Troicki's case to give him the chance of reselection if his appeal had been successful.

In 2010, Troicki won the decisive singles match in the final against France to give Serbia its first title.

Troicki's home federation described the verdict as "humiliating and disappointing."

"Serbia's Tennis Association is deeply disappointed with such a decision," it said in a statement. "Viktor Troicki has been inflicted a major injustice."

ITF President Francesco Ricci Bitti said rules had to be applied strictly "to keep our sport clean."

"What is harder to accept is criticism of doping control officers who perform a difficult role," Ricci Bitti said in a statement.

Top-ranked Rafael Nadal expressed support for Troicki, who he called "a good guy."

"I hope to see him back on tour next year," Nadal said at the ATP World Tour Finals in London. "The doctor who accepted to make the control the next day, if that's that way, that's a big mistake from the doctor, too."

The CAS panel acknowledged that the tournament anti-doping officer "should have informed the player in clearer terms of the risks caused by his refusal to undergo a blood test."

The court added "there was no suggestion that Mr. Troicki intended to evade the detection of a banned substance in his system."

The three-member CAS panel said Troicki and the doping official, a Ukrainian doctor, gave their evidence in good faith in Lausanne last month.

However, the panel's ruling published by the ITF noted that "the recollection of the athlete in particular was colored by his subsequent reconstruction of events."

A one-year ban was considered a "just and appropriate sanction" by the panel, and the minimum required in such a case according to ITF anti-doping rules.

The ITF tribunal in July declined to impose the standard two-year ban for a first anti-doping violation because it accepted Troicki was stressed by illness on the day and his long-standing needle phobia.

The ITF said Troicki remains disqualified from the Monte Carlo Masters, but retains his prize money and ranking points from subsequent events, including his run to a fourth-round loss against Jo-Wilfried Tsonga at the French Open.