NIKOLAY Davydenko is playing in the Rogers Cup tennis tournament this week amid an investigation into irregular gambling patterns on one of his matches.
The ATP said this week it had no plans to suspend the Russian or ask him to sit out.
Executive chairman Etienne de Villiers said: "It is important that we not jump to conclusions, especially when players' reputations could be unfairly tainted.
"What we must do is carry out a comprehensive and immediate investigation and that is what we are doing."
Davydenko is seeded fourth at the tennis tournament and will play in the second round today.
The ATP is looking into Davydenko's match against Martin Vassallo Arguello at the Prokom Open in Sopot, Poland, last week.
In an unprecedented move, British online gambling company Betfair voided all bets on the match when it drew about R70-million in wagers, about 10 times the usual amount for a similar match.
Most of the money was on Arguello to win, even after Davydenko won the first set 6-2.
Arguello won the second set 6-3 and was leading 2-1 in the third when the Russian retired.
Betfair has an agreement with the tennis organisation to report any instances of irregular betting. - Sapa-AFP
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