The England striker scored and missed a penalty in Bayern Munich's 4-0 preseason friendly win against his old club on Thursday.
Spurs chairman Daniel Levy has long admitted they have a buy-back option in Kane's deal after he was sold two years ago.
Now further details have emerged regarding the terms, with football.london reporting Kane had a buyout clause last January of £67m.
And in January 2026, that clause will drop to £54m. Spurs will be informed if any rival match their clause or make a significant offer for Kane. They can re-sign the veteran striker if they agree to match the bid.
"I don't really think about it," Kane told the BBC earlier this year.
"I really enjoy my time here, and I'm not thinking about being anywhere else. We have a great coach, a great team, and I just want to be as successful as I can with Bayern."