Dawson suffered the injury during Spurs’ 3-1 victory over Stevenage in an FA Cup fifth round replay on Wednesday.
Tests have now confirmed that the injury will keep Dawson out of action for 10-12 weeks.
A club statement read: “Scans taken this morning have determined that Michael Dawson is likely to be absent for a period of 10-12 weeks.
“The central defender was stretchered off in the first half of the FA Cup tie against Stevenage last night, with it now confirmed that he suffered a ruptured ligament in his right ankle.”