If you're not sitting down, take a seat. And a deep breath. We need to have what may be an uncomfortable conversation.

One day, center Ryan Kalil won't be playing for the Carolina Panthers.

It may not be imminent, but it's coming. And for an organization intent on building sustained success rather than a roster to win only in the present, it may happen sooner than later.

While plenty of talk at the NFL combine this week has centered around defensive end Charles Johnson, who's in the final year of his contract, so is Kalil, who in 2011 signed a big deal of his own just three weeks after Johnson.

Set to count $10.3 million against the cap in 2016, Kalil also looks like a prime candidate to be restructured this offseason. That could soften the current cap hit and add a couple seasons to his future.

After earning a Pro Bowl nod for the fifth time in his career, there's no question Kalil has some good years left. Because he'll be 31 and headed into his 10th season, it's fair to wonder just how many.

If that's a question on the Panthers' minds, there are some interesting options in this year's draft, including Alabama's Ryan Kelly, Notre Dame's Nick Martin and Michigan State's Jack Allen.

Two months before the Panthers have to make a decision with their pick at No. 30, Kelly appears to have the best chance to sneak into the first round. A three-year starter at Alabama, Kelly didn't allow a sack in either of his final two seasons. He also has experience with the type(s) of system Carolina runs.

"This year we did some more spread or hurry up, no-huddle stuff, which is a little bit different," Kelly said. "But coming from a pro-style offense ultimately helps in going to the next level."

Martin, meanwhile, has a pedigree similar to Kalil's. The younger brother of Cowboys' Pro Bowl guard Zack Martin, Nick won't be a top-5 pick like Kalil's younger brother Matt. But Nick Martin does have versatility the Panthers covet in their linemen.

"I’ve played both center and guard in college," he said. "I think being able to play all three of those interior positions is really big."

That's not a word associated with Allen, who at 6-foot-1 1/4 and 294 pounds, is the smallest lineman in Indy. But that's only an inch shorter and five pounds lighter than Kalil's measurements at the 2007 combine, and he's turned out OK.

"The biggest thing is technique wins, regardless of size. If you have the right technique and you’re doing the right things, it’s going to work out for you," Allen said.

"I don’t care if you’re short, but if you can play, you can play."

Indeed, and technique is how Kalil's won plenty of times the past nine seasons. It should also allow him to continue for at least a couple more.

After that? For the Panthers, it's a question at least worth wondering.