Chairman Daniel Levy wants the England striker to sign a new contract to avoid a repeat of the situation the club faced when Sol Campbell ran down his contract and left for nothing, although Defoe is not currently getting a game for Spurs.
"What I said to Jermain was that they have to push each other and when he gets his chance he has to take it," said Jol. "It is very healthy for the squad.
"I don't expect him to be happy about it, but I am not here to make people happy as I have to make tough choices.
"Like I said, I have named two strikers on the bench in the past, but it makes your job harder because you have to name a midfield player who can cover both wide and central positions."
The Dutchman added: "There are other players who will be disappointed, but the main advantage of this situation is that everybody must be on their toes for when they come back into the reckoning, which could be at any time."