"It was just a quick reaction save. I overstretched myself, heard a pop and that was that," he told Spurs' official website.
"I partially tore the tendon that connects the hamstring to the bone so it needs a little time to heal.
"It's gone well this season and this happened just when I'd started to play first-team football again.
"It's unfortunate because I was supposed to be at Luton for the rest of the season and it came at the wrong time for me.
"Hopefully I'll be able to start to do something before the season ends and then I'll have rehab in the summer and try to be ready for the Gold Cup with Canada.
"I have time on my side so I'm not going to push it but it would be great if I'm able to get back on the training pitch before the end of the season."