Tottenham lose Bale for up to two weeks
Bale was injured during the 3-0 Premier League win at Fulham that moved Spurs up to fourth place. He limped off after falling awkwardly following a shot at goal in the second half.
Spurs also lost defender Michael Dawson with a hamstring strain, though he could be fit for Saturday's trip to Everton.
"One [Bale] looks more serious than the other but nothing too major," Villas-Boas told Sky Sports. "Both players will come in for treatment very soon.
"When there is a muscle [injury] you have to take into account one or two weeks. We will try to restrict that as much as we can."