Back in May, I noted that Chipper Jones' hot start had him on pace for one of the greatest final seasons in MLB history. Well, he hasn't quite kept up that pace, but he's still poised to go out with some excellent numbers, including a .292 / .381 / .466 slash line in 431 plate appearances. That's good for just short of 3 wins above replacement (WAR), by both FanGraphs' and Baseball-Reference's reckoning (2.9 for the former, 2.6 for the latter).

A total of around 3 WAR is merely somewhat above average for a normal everyday player, but for an old guy in his final season it's practically historic. Using Baseball-Reference's search tools, I looked for all players since 1901 who posted at least 2.5 WAR in their final seasons while playing at an advanced age (35+*). There haven't been very many.

* This weeds out many of the players whose careers ended early due to tragic deaths or being banned from baseball, providing a more apt comparison group.

Chipper's WAR is still in flux (it can go up or down, though it's more likely to go up), but if he stays at 2.6, he'll trail just 9 players--7 of whom are Hall of Famers. Even the worst players on the list--Javier and Grady--were still pretty good, earning over 20 brWAR in their careers.

Some of the notable players to just miss the list include Larry Walker (2.2 WAR in 2005), Mickey Mantle (2.2 in 1968), and Ty Cobb (1.7 in 1928).

Looking further at the ages of the players, you'll note that before Chipper, only two players in their 40s had posted a WAR above 2.5 in their final years. Those two players--Barry Bonds and Ted Williams--rank among the 4 or 5 best hitters of all time.

Also of note is that Chipper has played 99 games at third base; assuming he plays at 3rd again tonight, he'll become one of a select few oldsters to play 100 games at 3B in their final seasons. In fact, only 9 players have done it in their final years at age 35 or older. Of those, only Tony Cuccinello (see above) and Carney Lansford (2.4 WAR in 1992) were at all productive.

As I'm sure Chipper understands better than anyone, 3rd base is a tough position to continue to play every day into one's late 30s and 40s; to play it relatively well is even more difficult. Anecdotally, anyway, it seems that 3rd basemen wear down more quickly than most other positions, which may explain why they are under-represented in the Hall of Fame.

Think about this: Chipper is going to be just the 4th player to play 100 games at 3B at age 40 or older since 1901. Graig Nettles did it twice, Lave Cross did it way back in 1906, and Cal Ripken did it in his final season. That's it. Nettles is the best comp for Chipper, and like Chipper, he was pretty good at age 40 (3.0 WAR); however, Nettles fell off sharply the next year (0.2 WAR) and was never any good after. Cross was decent at 40 but sucked at 41, then retired. And of course Ripken wasn't even a 3rd baseman by trade (plus he was awful at age 40). So what Chipper is doing is very rare indeed.

It may seem funny at first, but despite all the injuries (large and small), Chipper Jones is actually one of the most durable 3rd basemen of all time. He doesn't hold a candle to Brooks Robinson in that regard, but who does? This will be Chipper's 14th season of 100+ games played at 3rd base. Only 4 players (Robinson with 17; Mike Schmidt, Eddie Mathews, and Nettles with 15) have more**. If not for Vinny Castilla, Chipper might have more such seasons than anyone but Robinson. (Or not; maybe Chipper breaks down more or retires earlier without that LF hiatus.)

** I should mention, though, that Adrian Beltre is also sitting at 14 seasons, counting this year. He will almost certainly get his 15th next year. Surprised? I was.

By stepping away after this season, Chipper Jones will become the first great 3rd baseman to retire while he's still a valuable player. Of the top 10 3rd basemen of all time by career brWAR, Chipper is the only one to play at much above replacement level in his final season. He just decimates the field:

*** Scott Rolen is, of course, still active; however, he's posted just 0.3 brWAR this year and seems unlikely to play much longer or much better. Crazily, that 0.3 WAR actually looks pretty good by the standards of the final seasons in the table.

Of these all-time greats, only Nettles and Boggs were older than Chipper, only Brett had more PAs or homers, and only Boggs hit for a (slightly) better batting average. However, Boggs' overall offense was actually a bit below average for 1999 despite that good BA, as his OPS+ was 94 (Total Zone thought Boggs' defense was atrocious as well). Indeed, none of the other players posted an OPS+ above 100; Chipper is at 127.

Thanks to his knees, Chipper is not a great defensive 3rd baseman, but for his age, he's doing quite well. Most of the players on the list above had terrible defensive ratings (and several weren't even 3rd basemen anymore). The advanced defensive metrics place Chipper at slightly below average relative to the league as a whole, but the league as a whole is a lot younger and has had a lot fewer knee surgeries than Chipper, so I'd say he comes out ahead all things considered.

With all of these other great players ending their careers in ignoble fashion, it is no wonder that Chipper sought to end his career on his own terms. I know it seems from our vantage point that Chipper could play productively in 2013, but with the state of his body and the above track record of top 3rd basemen, such a feat seems to me like it would be just short of a miracle. Heck, what Chipper has done this year at age 40 is astonishing enough.

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I've seen a few pundits wondering about the hoopla surrounding the Chipper Jones Farewell Tour, specifically asking why Chipper is being singled out from the pack of great retiring players over the years. I think the answer is contained in the tables above. Hardly anyone gets to leave the game of baseball in the way that Chipper is doing it. Name the last player who A) announced his retirement in advance so he could be honored, B) still played regularly and well, and C) did it in the city where he had his best seasons.

I can't think of anyone else who fits that description. You can rest assured, though, that if Derek Jeter (for example) gives us advance warning of his retirement, he'll get at least the amount of celebration that Chipper has gotten.

Most players, even great ones, go out with a whimper, and the rare ones who manage a last-season bang don't usually announce their retirement in advance. Chipper has done a huge favor for his fans around the country by giving them a chance to say goodbye while he's still not too far from being the Chipper of old.

So thanks, Chipper. Here's hoping that your last postseason goes as well as your last regular season.