A few years ago, it was clear who the Sharks were building around. Joe Thornton, Patrick Marleau, Evgeni Nabokov and Dan Boyle were the core, the vital organs of the San Jose franchise.

That, however, seems to be changing.

Don't take this the wrong way. Aside from Nabokov, whose time with the Sharks is gone, I've just named three players on whom the Sharks success next season hinges upon. Joe Thornton remains the captain and likely scoring leader, Patrick Marleau has become a dependable source for thirty to forty goals a season, and Dan Boyle is the foundation of the team's now formidable blue line.

However, when you look at the Sharks roster, you begin to see that these players aren't as young as they once were. And while they still have some serviceable years ahead of them, the elite "core" may not be as exclusive as it once was.

All you have to do is look at some of the Sharks recent signings. After trading for Brent Burns, a young all-star defenseman, and signing him to a long-term contract, the team extended the burgeoning Logan Couture for two years beyond the upcoming season. Marc-Edouard Vlasic is inked for the next two years as well, as is Jason Demers.

Just one of those players is over 25 (Burns, who is 26). Add to that group of youngsters Joe Pavelski and Ryane Clowe, who are 27 and 28 respectively, and you have yourself a decent building block.

That's something the Sharks will need in the future.

Thornton, Marleau and Boyle still have some good seasons in them, and if the Sharks are going to advance to the Stanley Cup Finals for the first time in team history, these players will have to be a big part of that. They won't be around forever, though.

Luckily, even as general manager Doug Wilson has played fast and loose with his first round draft picks (only two first rounders [Couture and Nick Petrecki] selected by San Jose since 2000 remain with the team), he's built a roster that will remain competitive even as Thornton and his crew enter the twilight of their careers.

It may not yet be a changing of the guard, but the replacements are definitely in waiting.