People here are tossing around figures like $7million.
As a Leafs fan all I can say is that I hope one of the other 30 teams in the NHL are the ones offering him that. He is a good offensive defensman, but that kind of money would be much better spent elsewhere (eg. being put towards signing Marner, Kapanen and Johnsson). Frankly with Toronto getting another LHD recently in Muzzin who is both cheaper (for one more year after this season) and overall better we can afford to let Gardiner walk.
Beaides, behind Morgan Rielly (and his stupidly good $5million contract), Muzzin and Zaitsev (whose contract is...less good), the Leafs have Dermott who looks ready for full-time second pairing duty and Liljegren who has been solidly developing in the AHL and should be ready for 3rd pairing time next season.