Sporting briefs

Foreign refs: Levski Sofia owner Todor Batkov has threatened to withdraw the club from the Bulgarian championship if authorities reject his demand for foreign referees to officiate his team's matches. Batkov's threat comes a day after the Bulgarian Football Union (BFU) rejected Levski's accusations that authorities are trying to "pre-determine" the championship.

Martins: Wolfsburg striker Obafemi Martins will miss the rest of the calendar year due to a shin problem which requires surgery. The Nigerian forward will have an operation on his left shin this week, ruling him out until the new year. Martins was originally scheduled to go under the knife at the end of the first half of the Bundesliga season on December 20, but that has now been brought forward since the player is currently unable to even train.

Villa's Clark: Aston Villa's promising central defender Ciaran Clark has signed a new two-and-a-half-year contract with the Midlands club. Clark, who made his Premier League debut against Fulham earlier this season, has committed himself to Villa until the end of the 2011-2012 campaign.

Estudiantes: Holders Estudiantes will open their defence of the Libertadores Cup against Bolivia's Bolivar, a Peruvian team and a qualifier from play-offs following Friday's draw of South America's prime club competition. The South American Football Confederation (CSF) said the tournament would begin on Jan. 27 with the final on Aug. 18, later than usual after a break during the June 11-July 11 World Cup.

Aguero: Atletico Madrid striker Sergio Aguero has dismissed media reports of a possible move to Chelsea in January. "I want to help Atletico get out of its current problems. I am committed to the team and I'm not moving in the winter, whatever people say," the Argentina international said.

Cricket: Former captain Graham Gooch will join the England coaching staff to help preparations for the first test with South Africa, the England and Wales Cricket Board announced yesterday. Gooch, who played 118 tests for his country, will work with England's batsmen on a temporary basis in the build-up to the test in Centurion starting on Dec. 16.

Doping: Disgraced speedskate star Claudia Pechstein, suspended for two years over anomalies in her biological passport, said she still hoped to clear her name in Germany. "All work of investigation will clear me," Pechstein said. The Court of Arbitration for Sport (CAS) last week upheld the two-year doping ban against the five-time Olympic champion in a case which sets a precedent. Pechstein never failed a drugs test but sport's highest court accepted the validity of the biological passport in the fight against doping.

Hockey: Defending champions Australia, Olympic champions Germany and the Netherlands successfully launched their Champion Trophy campaigns with opening day victories in Melbourne yesterday. Australia blasted South Korea 4-0, Germany edged out England 3-2 and the Dutch saw off Spain 3-2 to stake early claims for the December 6 final of the top-six ranked teams' tournament.

Basketball, NBA: The Oklahoma City Thunder eased to a 108-90 victory over the Milwaukee Bucks on Friday, Kevin Durant leading the way for the much-improved franchise with 33 points and 12 rebounds. The 21-year-old forward made 10-of-21 shots and drained 12 free-throws as the Thunder (9-7) notched their ninth victory around two months earlier than last season, when they finished a lowly 23-59.

Rugby Union: Italy captain Sergio Parisse will miss the Six Nations after it was confirmed yesterday he is to have surgery to rebuild the anterior cruciate ligament in his right knee. The number eight, replaced as captain by Leonardo Ghiraldini for yesterday's test with Samoa, suffered the injury on Thursday. Doctors said it was likely the Stade Francais player would be out for up to six months. The Italian rugby federation said in a statement surgery would take place in Milan today.