ATP chairman Adam Helfant has confirmed the governing body will not be reinvestigating Andre Agassi's positive drugs test in 1997 and cannot impose retrospective sanctions.

The American stunned the tennis world with the revelation in his recent autobiography that he failed a test for crystal meth and then lied about how it came to be in his body to avoid a ban.

The reaction from within the game has been mixed, with Andy Murray and Andy Roddick supporting their boyhood idol, but Marat Safin calling for Agassi to give back his titles and prize money.