For the Red Sox, the current run of exceptional play likely comes as much as a source of relief from anxiety as it does as cause for excitement. And for the rest of baseball world, the run is daunting beyond its implications for the 2011 season.

By and large, the Red Sox lineup that is currently steamrolling through its schedule – most recently, with Sunday’s 14-1 mauling of the Blue Jays (recap) – is built to last. It is a roster that was constructed not merely for the current season, but for years to come.

The fact that the team waved goodbye to 32-year-olds Victor Martinez and Adrian Beltre while welcoming 29-year-olds Adrian Gonzalez and Carl Crawford had significant implications for the team’s demographics. The team replaced a pair of players who were at the back end of their prime years (perhaps even slipping just beyond them) with two players who should be at the height of their powers, at least based on their ages.

Here’s a breakdown by age and remaining years of team contract control of the lineup that is currently pillaging opposing pitching staffs:

Jacoby Ellsbury: 27 (2013)
Dustin Pedroia: 27 (2015)
Adrian Gonzalez: 29 (2018)
Kevin Youkilis: 32 (2013)
David Ortiz: 35 (2011)
Carl Crawford: 29 (2017)
Jed Lowrie: 27 (2014)
J.D. Drew: 35 (2011)
Jarrod Saltalamacchia: 26 (2013) / Jason Varitek: 39 (2011)

Yes, the team will have some decisions to make this coming offseason. Foremost will be whether Ortiz (who is hitting .325 and leads the club in OBP (.395), slugging (.624) and homers (17)) should be brought back. The team will also have to decide what to do in right field, since J.D. Drew’s contract is expiring. (Ryan Kalish was expected to be the likely right-fielder of the future starting in 2012; it remains to be seen whether his recovery from a shoulder injury impacts that assessment.) And, while Lowrie is under team control for three more seasons beyond this one, the team has an ongoing assessment to make about when Jose Iglesias is ready to graduate to the majors.

All of that said, the core of the Sox is secure for years to come. After Drew and Ortiz (as well as Jason Varitek, currently working in a timeshare with Jarrod Saltalamacchia behind the plate), none of the current Sox lineup members is eligible for free agency until after the 2013 season (assuming that the Sox exercise their 2013 team option on Youkilis). That is no accident in the current market for acquiring the services of players.

“If you have the right players under control, it’s a great thing. They can develop familiarity with one another and create a tremendous amount of organizational stability,” Sox general manager Theo Epstein said earlier this season. “Generally speaking, in a market when there are really good, impact-type players freely available, you don’t want a lot of players tied up.

“But in a market where more and more players are getting tied up, fewer impact players are hitting free agency, there’s fewer great players available in trades, you want to have your good players under team control. So I think the contract status we have for most of our players is a function of the fact primarily that we believe in this group of guys, but also it’s a reflection of the fact that we see an increasingly competitive market with fewer impact players getting to free agency. So having more control and less flexibility than we had, say, six or seven years ago could be a good thing.”

The Sox have faith in the ability of this core in no small part because of its relative youth. Different teams define the prime years in different ways. The Sox, according to assistant GM Ben Cherington, consider the ages of 27 to 31 to be prime years, with that definition having shifted slightly downward based on increasingly sophisticated understandings of defensive metrics. (A player like Iglesias, for instance, is already at or near his defensive prime, while he is still several seasons from growing into his offensive prime; his peak total value as a player, therefore, will come a bit earlier than his peak offensive value.)

An executive of another team suggested that the ages of 27-32 offer a rough guide to the prime years, with concerns about decline intensifying as a player reaches age 34. That helps to explain why the seven-year deal between the Nationals and outfielder Jayson Werth was treated with widespread scorn this winter -- the first year of his deal comes when he is 32 years old; his $21 million salary in 2017, when he is 38, likely will be an albatross.

The Sox currently feature four star-caliber players in their 20s (Ellsbury, Pedroia, Gonzalez, Crawford). In Lowrie and Iglesias, they have shortstops who should still be on the upswing of their careers. The same is true of a prospect like Kalish who is expected to contribute as a big league regular, perhaps as soon as next year.

All of that reflects the importance that the team attaches to having players who are in their primes. Obviously, it was willing to pay dearly (in prospects and dollars) to acquire Gonzalez and Crawford because both players have established an All-Star-level baseline of production, and barring injury, they should continue to perform at or near that level for at least the next few years. Opting to add a pair of 29-year-olds, and letting 32-year-olds Beltre and Martinez depart, represented an important part of constructing a roster with players for whom decline is not yet a major concern.

“Practically speaking, it’s just very hard to put together a roster of prime age players,” Sox Assistant GM Cherington explained last month. “You’re going to have to fill in somewhere with somebody, usually a free agent. And usually, free agents are not prime age players.

“But teams that have sustained success over a long period of time generally have a core of prime age players, and they’re generally able to turn that core over and maintain a core even if the names change over time. The Braves and Yankees, the early years of their success, they were able to do that. …

“The teams that have gotten in trouble, the teams that had a period of sustained success and then got in trouble often get caught up in a web of having a critical mass of players who have moved too far past their prime and can’t do anything with them, whether because of long-term commitments or whatever. They’re locked into this critical mass of players that’s declining.”

Injuries, of course, could change the picture of the Sox and the current rosy glow emanating from their key position players. And there will come a time when the Sox are facing declines from current everyday players who are currently at their peaks; just as J.D. Drew appears to be at that point at age 35, so, too, will Youkilis, Crawford and Gonzalez likely (though not certainly) face dropoffs as they enter their mid-30s. But that scenario is years away from unfolding, by which time the Sox will likely have gotten younger with other members of their core, a fact that is hardly accidental.

For now, the Sox have seemingly hit their stride, and they have the potential to sustain it not just for the rest of 2011 but for seasons to come. At a time when the Yankees lineup features six players in their 30s, with a great deal of conversation about the team this year focusing on the declines of longtime anchors Derek Jeter and Jorge Posada, the Sox are making noise in a fashion that suggests that they are poised to do damage over the long haul.

“We have a lot of prime years, both in the free agents and young players, we have a lot of prime years ahead at this point,” said Epstein. “It all comes down to making sure you have the right players. This is a group that we believe in, not only for this year but also going forward.”