Bale, 21, has been missing with a back injury since January, is yet to return to full training during mid-season break in Dubai.
Welsh wizard: Bale has already terrorised one half of Milan after two stunning performances against Inter
He is rated extremely unlikely to make the second leg against Milan, which Spurs go into with a 1-0 lead.
Meanwhile, Tottenham manager Harry Redknapp believes only five clubs can finish in the top four after Liverpool's 3-1 defeat at West Ham on Sunday.
'The top five now will be the top five at the end of the season for sure,' he said. 'It is so important for us and we want it again,' added Redknapp.
?Spurs back in the market for ?15m Manchester City defender Richards Defoe scare not serious, says Harry after striker breaks down in DubaiSpurs chief Redknapp in the market for out-of-favour Barca striker Bojan
?Explore more:People: Gareth Bale, Harry Redknapp Places: Milan, Liverpool, Dubai
Source: Daily Mail
Source: Daily Mail