Defoe was substituted in the first-half of the 1-0 victory over West Brom at The Hawthorns after going over on his ankle.
Spurs manager Andre Villas-Boas has confirmed the player will have checks on the extent of the injury in the next 24 hours.
"I am extremely happy with the win - apart from the injury to Jermain Defoe," he said. "He rolled his ankle. He will have to have a scan to reveal the extent of the injury.
"Hopefully there is not a lot of ligament damage. If there is, he could be out for two to three weeks. Has he been withdrawn from the England squad? Yes he has."
Defoe's absence would severely blunt the Tottenham forward line as fellow striker Emmanuel Adebayor is currently on international duty with Togo.
But Villas-Boas defended the club's failure to land Brazil international Leandro Damiao on deadline day.
Spurs had a late bid rejected for a player whose part-third-party ownership has proved a stumbling block to a deal in the past.
And Villas-Boas said: "It wasn't something we just did on the last day of the window. Third party ownership makes it difficult to do."