Defoe could be heading back to the Premier League after just five months playing for Toronto in the MLS.
Sky sources understand Leicester want to talk with the former England and Tottenham striker, who is interested in returning to England.
Defoe has been linked with a move away from Toronto following the sacking of Ryan Nelsen as coach after their 3-0 defeat by the New England Revolution on Saturday.
Toronto general manager Tim Bezbatchenko confirmed that a bid had been made for the striker from an undisclosed club
Bezbatchenko said: "We have received an offer and have discussed it internally.
"When you have scored as many goals as he has, and have the reputation and background that he has, then it's not uncommon to receive these offers.
"We have received multiple offers before, and in the course of this year, so I want to confirm that we are in talks.
"We are not 100 per cent committed in what we are doing and we have to sit down and talk about what is the best plan of action."
Leicester have been amongst the busiest clubs on Deadline Day. They have signed Swansea youngster Kris Scott, and are attempting to sign Manchester United duo Nick Powell and Tom Lawrence.
Powell, who spent last season on loan at Wigan, is expected to once again move on a temporary basis until the end of the current campaign.
However, the deal being discussed for Lawrence is thought to be a permanent one.
Highly-rated attacking prospect Powell moved to Old Trafford from Crewe in 2010 and has gone on to make seven appearances for United.
The 20-year-old made 41 appearances during his loan spell with Wigan, scoring on 12 occasions.
Forward Lawrence was handed his first-team debut for United by interim manager Ryan Giggs at the end of last season in the 3-1 win over Hull City.