Before the season began, Baseball Prospectus had already projected the balance of Derek Jeter‘s career-we said that it would end in 2013. Now that he almost has all of a season that rates as a 90th-percentile season for PECOTA‘s pre-season’s projections, it’s worth asking not simply how far out the window we can chuck that, but whether or not Jeter’s career is ever going to end. Consider the performance:

Jeter Season      AVG/ OBP/ SLG/ EqA
2008 Actual      .300/.363/.408/.283
2009 Projected   .289/.354/.384/.273
2009 90% Proj.   .327/.395/.483/.305
2009 Actual      .330/.396/.474/.302
2009 Translated  .325/.393/.485/.301

I’ve italicized the projected or translated info to offset it from the real deal. Because we have to make allowances for NuYankee and couldn’t anticipate fully the impact of the park, for the 2009 projections and translated performance, I’m using Clay Davenport‘s Normalized translations of the projected performance, which adjust for park and league and tell us what a player would do in a standardized environment. A 90-percent projection is the kind of year that a player’s capable of producing about 10 perecent of the time, spun from his Equivalent Average, from which his other data gets spun out given the shape of his past contributions.

So, looking at all that, we certainly didn’t bulls-eye Jeter’s 2009 season. We can’t really say we bulls-eyed the kind of great year he had a 10 percent shot at having, as much as we can say having that one-in-ten great year, we correctly suggested what that would look like as far as his seasonal line. All it took was Jeter to go out and have a great season.

Understand that our baseline projection of him was built on the back of that disappointing 2008 season, or a season that was disappointing perhaps by his own standards alone. That projection is still better than most members of the shortstop universe, but with the expectation that Jeter was headed into his age-35 season and the fact that Jeter has very few historically comparable ballplayers-the closest was Dick Groat‘s 1965 season, and it wasn’t really all that similar-PECOTA adopted an understandable conservatism with the Captain.

What’s especially interesting about Jeter’s season is that he’s managed to step up on the defensive side of the equation, or perhaps more properly, he’s not losing any ground. After mid-career problems in terms of his fielding performances that had his translated fielding rates (scaled to 100) bouncing in the 80s, and given the extended arguments between mainstream perception that he’s been a great defender and sabermetric evaluations that tend to suggest he’s been awful, it’s worth recognizing that Jeter’s managed to retain his defensive virtues really very well. Translating his defensive rates in recent seasons has him at 98 or 99-a tick below average, but when he’s cranking out years this good at the plate, the sort of thing that doesn’t merely make Jeter valuable, it puts him in the mix for a down-ballot selection for the league’s Most Valuable Player. Consider the top 10 players in the American League by WARP3, or BP’s total value stat that rates fielding, pitching, hitting, baserunning, the works, measuring a player’s value in wins above replacement players over 162 games:

Rk Player       WARP3
1  Joe Mauer      10.8
2  Zack Greinke   10.0
3  Evan Longoria   9.4
4  Marco Scutaro   8.9
5  Roy Halladay    8.3
6  Shin-Soo Choo   8.2
7t Mark Teixeira   8.1
7t Chone Figgins   8.1
9t Derek Jeter     7.6
9t Ichiro Suzuki   7.6

Not bad for an old man we were pushing towards the downslope of his career, even if it still boils down to another argument for Joe Mauer’s worthiness to win the hardware. Take the pitchers out of the picture for the sake of argument, and it’s safe to say Jeter commands (and deserves) more recognition among the league’s best position players than career years from Scutaro or Choo earn them.

But to return to what this level of performance and his sustained usefulness at shortstop means for Jeter’s future and how long he’s going to be playing, let’s start with the specific and work up to the big picture. First, it means that we can expect that he’s going to keep playing shortstop for a while yet. Second, we need to go back to that initial forecast that his career would end in 2013-in that age-39 season, we said he’d deliver a translated performance of .292/.355/.397 and a .265 EqA. That’s not exactly the sort of year at the plate when you take Old Yeller out back and shoot him, not when the average shortstop’s hitting .269/.328/.392 and a .254 EqA.

Headed into trying to make a PECOTA projection for 2010, we can anticipate that those rates are going to be headed upwards over the next several seasons as a result of a short-list MVP-level season. Given Jeter’s continued value at short, it’s safe to say that he’s going to deserve better consideration for extended career length as well. So when’s the end going to come for the Captain? Given that we’ve yet to project a point in time that he can’t hit well enough to contribute, and that he has yet to struggle, even if he finally does have to move off of short, it looks like he’s still going be able to help a club without regressing to the sort of career-ending utilityman’s contributions that Alan Trammell‘s career wound down to, for example. Perhaps the only thing that might end Jeter’s career after the next four or five years is a decision from him on the basis of no longer being able to play short, or not being satisfied with what’s left to him as age slowly claims other elements of his game from him. If ever there was a all-time great player primed to end his career on his own terms sometime in the now more distant future, and not after some Steve Carlton-like crawl from one last gig to another, it’s the Captain.

A version of this story originally appeared on ESPN Insider Insider.