World number one Jannik Sinner has been cleared of any wrongdoing after twice testing positive for a banned substance in March.
The Italian tested positive for low levels of a metabolite of clostebol - a steroid that can be used to build muscle mass - during Indian Wells.
A further sample taken eight days later also tested positive for low levels of the same metabolite.
A provisional suspension was automatically applied but, as Sinner challenged it successfully, he was able to keep playing.
The International Tennis Integrity Agency (ITIA) carried out an investigation which found Sinner was inadvertently contaminated with the substance by his physiotherapist.