It will depend on how plausible his explanation is, but normally the anti-doping agencies are showing no mercy in those cases whatsoever and he can expect to be banned for years. But doesn't that mean he can still play for clubs in a different association like in Saudi Arabia? I guess it wouldn't hurt him that much if the consequence is that he is now forced to earn 30 million per year playing for a club in the Saudi Professional League. Unless I am missing something here and any ban imposed by the UEFA/FIFA? is valid globally or something, but I don't believe so.
After I read from several sources the news about how many years he will be banned from football some say only one year and some say several years but from my own assessment it looks like UEFA will ban him for several years because the use of doping is so deviant from football that it looks like it will be a very long time for him gets the ban and if he can still appear but in other leagues such as Saudi Arabia, the question is whether any club from Saudi Arabia wants to sign a player who has previously used doping or drugs?
I still imagine that because the majority of Saudi Arabia is Muslim and drugs are prohibited or haram and it seems that Saudi Arabia doesn't want to take this risk.