The older the Celtics get, the closer that window gets to slamming shut. The Celtics are running out of time to win another championship, and with their nucleus of veteran stars inching further into their thirties, the pressure is building.
That puts Rajon Rondo in a unique situation.
The Celtics point guard, who turned 23 toward the end of last season, is the one glimmer of hope for a team striving to still be in the conversation past 2012. He's surrounded by veterans whose clocks are ticking away, and yet Rondo himself is one of the biggest rising stars in the game.
That's why the Celtics should do everything in their power to keep him around.
As a first-round draft pick, Rondo is entitled to four years of NBA service time before he hits restricted free agency. Being the No. 21 overall pick back in 2006, Rondo already has three years under his belt, and he finished the third one by terrorizing the Bulls and Magic in the first two rounds of the playoffs.
He was a triple-double waiting to happen. The Celtics were undermanned and undersized with Kevin Garnett and Leon Powe on the shelf, and they needed someone to carry them. That's exactly what Rondo did: He carried the Celtics on his back to the seventh game of the Eastern semifinals with the eventual conference champions.
The Celtics know that, eventually, Rondo's little monthlong fantasy will turn into the real thing. In due time, he'll be the go-to guy every night, not just a backup plan when injuries arise. When the C's Big Three (or four, if you will) passes on, Rondo will be the guy to build a team around.
Between now and July 2010, Danny Ainge has some work to do. He needs to convince his enigmatic young point guard that while the 2010 free-agent class is glitzy and glamorous, the open market isn't for him. Boston is the place to stay.
It's a hard sales pitch to make. But Rondo does appear ready to listen.
Rondo is all about going to the team that respects him most. He wants to feel wanted, wherever he goes. The Celtics have a year to convince him that they want him right here.
"If the Celtics want me, then I'd be happy to stay," Rondo told Sports Illustrated this week.
Why wouldn't they want him? He has the talent to be a franchise player. He's an athletic, dynamic, constantly improving point guard with the ability to run a team offensively and defensively. As far as leadership goes, he's still growing, but he's in the right place to learn, with four of the game's best veterans around him.
In a few years, Rondo will be the face of the franchise. Ainge is a smart guy — he knows that.
"Rajon is in a situation where we certainly want him and consider him a big part of our future," Ainge told the Globe last week.
"This time of year," he continued, "it's one of those circumstances where we would want a deal that's good for us and gives us security, and he wants a deal that's good for him. I think we'll know after a few conversations if we are close and whether we can get a deal done or not."
If those conversations happen now rather than next spring, it's in the Celtics' best interest. The closer Rondo gets to joining LeBron James, Dwyane Wade and Amare Stoudemire in the 2010 free-agent frenzy, the riskier it becomes for the Celtics.
"I've got some time to see how things settle in Boston," Rondo told SI's Paul Forrester. "If it doesn't, I'll play out the fourth year and see how things go next summer."
Knowing Rondo's pattern of growth so far, that fourth year could be even better than the third. Maybe the C's should lock up their rising superstar now, before it's too late.