However, Villas-Boas believes that his squad contains enough good replacements to deputise for the injured trio.
"We still have a big squad and the ability to adapt. We just have to play against Everton and see when these players get back to make us even stronger.
"We've played without Bale before and we've got the results that we needed, results that have put us in the position we are in the league. We recognise the form the player is in and the squad will step up a level for his absence. Key players are always missed by any team but we have played without him before.
"Gallas may have a small tear on his calf but again it is about the assessment on Friday."
Spurs face Everton on Sunday.