He was the subject of trade rumors (via RDS) earlier this month involving the Flyers. However, unless the Flyers want to part with young players like Sean Couturier, don't expect a trade between these teams involving Subban to ever get done, if it is ever discussed again.
Age of Defense
Take a look at the ages of the notable defensemen currently on the Flyers' roster:
The Flyers aren't exactly stocked with young defensemen who can play major minutes for a Stanley Cup contender.
Braydon Coburn is a solid player, but not a true top-pairing player.
Luke Schenn is arguably the most promising young blueliner on the Flyers, but playing in Philadelphia will be an adjustment for him after several years with the Toronto Maple Leafs.
Erik Gustafsson and Marc-Andre Bourdon both have have potential, but they aren't anywhere near as talented, or experienced, as Subban.
Subban knows what it's like to play in a major hockey market, so going to the Flyers probably wouldn't be a difficult change for him. At 23 years old, Subban is a young defenseman whom the Flyers can build around going forward.
The Flyers' injury woes on the blue line have been a consistent problem that doesn't seem to be going away anytime soon.
Pronger has yet to make significant progress in his quest to return from a concussion, and Lilja and Meszaros are currently recovering from injuries too.
As I've mentioned in the past, Subban's durability is an important part of his game, which makes him a quality option for a Flyers defensive group that is rarely at full strength.
For the Flyers to contend in the Eastern Conference, they cannot go long stretches of the season with injuries hurting their defensive depth.
Who Will Replace Matt Carle's Offense?
Matt Carle's offensive production will be sorely missed next season, and the Flyers still haven't found anyone to replace his scoring from the blue line. He was one of the two Flyers defenseman who scored more than 30 points last year.
Schenn scored 22 points last year and has the chance to improve on that total since he will have a lot more offensive talent around him in Philadelphia, but he won't reach 40 points next season.
Subban is the ideal offensive defenseman to replace Carle's offense while Lilja and Meszaros are injured. Since the Flyers have so much more offensive talent than the Canadiens do, Subban could reach 50 points if he played a full season in Philadelphia.
Subban totaled 36 points on a Montreal team that ranked 19th in goals scored per game during the 2011-12 season.
Do the Flyers Have Enough Defensive Talent to Compete in the East?
Last season, 10 of the 15 highest-scoring teams in the NHL were in the Eastern Conference, including the Flyers.
The Carolina Hurricanes and Buffalo Sabres both finished outside the top 15 last year, but could certainly finish in the top half of the league in goals scored per game next season after making some strong additions via free agency.
The Flyers are going to have to show some impressive defensive fortitude next season to win games in a tough Eastern Conference. If the Flyers don't make any changes to their current group of defensmen, they won't have enough depth or talent to get back to the Stanley Cup Final next season.
Since the Flyers probably aren't willing to trade young forwards with great potential, such as Couturier and Brayden Schenn, then trying to bring a defenseman of Subban's caliber to Philadelphia using the offer-sheet strategy must happen.