The Celtic boss is ready to try and tie the Kenyan down on a longer contract and will help chief executive Peter Lawwel pursue this by speaking to the player's agent, Rob Moore.
The boss said: "We can re-open negotiations with Rob on Victor's situation.
"He's under contract for another two years but, obviously, the longer we leave it, the more vulnerable we become, or the more he becomes an attractive proposition for a bigger club.
"That scenario will be a reality probably later on down the line. In the meantime we will be plugging away at it."
Celtic have made what they believe is a generous offer to Wanyama, who signed from Belgian club Beerschot 18 months ago.
Lennon accepts the player may want to test himself in the Premiership.
"That's the reality of the job sometimes with players," said Lennon.
"He has never intimated he wants to leave and I'm not too sure who is driving the bus in this situation, him or Rob.
"Further down the line I'd like to speak to Rob again on the situation and see if we can bed him down for a little bit longer."
Lennon said Celtic have not received bids for Wanyama, or any of their players, despite speculation Norwich want Gary Hooper and Portland are pursuing Paddy McCourt.
"We want Gary to stay, and we're in negotiations with him," said Lennon.
"There's a lot of speculation about him but I've not spoken to anyone."
On McCourt, who could fall further down the pecking order if Tom Rogic is signed, Lennon said: "Paddy hasn't said he wants to leave.
"The reason he hasn't played so much is that injuries have curtailed him."