At first glance, one would be likely to ask why Toronto would ever consider giving up a player like Gardiner. He's a young, talented, offensive defenseman who is just starting to hit his stride.
But the Maple Leafs recently signed Dion Phaneuf to a seven-year contract extension for $7 million per season, Cody Franson's contract is up at the end of this year, and 19-year-old Morgan Rielly looks like an even better version of Gardiner.
The Leafs also have some serious needs, and therefore Gardiner may be expendable. Back in October, Darren Dreger mentioned the possibility, and then in December Pro Hockey Talk reported that Toronto may consider moving the 23-year-old.
Gardiner would fit in perfectly with Philadelphia. They sorely need some more youth, offensive instincts, and speed on the blue line.
Toronto would likely want a top forward in return, but the Flyers certainly have some bargaining chips. They could dangle guys like Scott Laughton, Nick Cousins, Michael Raffl, or Scott Hartnell. Besides Laughton, it would take a combination of those other forwards with another defenseman and/or draft picks.
While it's probably the least likely target on this list, it's not out of the realm of possibility.