Sherwood believes Tottenham have 18 months to keep Harry Kane.
The former Spurs boss believes Jose Mourinho will need to prove to the striker the club can win trophies.
“[Kane] needs to win something. So I think he'll give it a period of time, certainly next season," Sherwood told beIN Sports.
“The end of this season and next season and see if they can get closer to winning something. And if they don't, then he will leave."