Adrian Beltre, the Dodgers’ 25-year-old third baseman, is having a magnificent season. He’s hitting 342 AVG/.389 OBA/.658 SLG, and is on pace to hit 50 home runs playing half his games in spacious Dodger Stadium. He also might be the best defensive infielder in the National League.

Unfortunately for Beltre, his season can’t erase the memory of the first six years of his career. He made his major league debut at the age of 19 in 1998; when he hit for an .830 OPS at age 21, he seemed to be on his way to becoming a superstar near Alex Rodriguez’s level.

But Beltre not only didn’t become a superstar, but seemed to regress every year, to the point where he was not merely failing to live up to his potential, but was actually worse than an average player. In 2002,his on-base average was .303; last year, it was .290.

This was failure of historical magnitude. Only 17 players in the postwar era had or have more at-bats than Beltre has through age 25; 11 of those are Hall of Famers or locks for election, and the others – players like Cesar Cedeno and Vada Pinson – are just a step down from that level. All told, Beltre came into this season looking like one of the greatest wastes of potential in baseball history.

That changed this year, when all the extraordinary talent and skills he has shown throughout his career have come together. As Beltre will be a free agent after this season, he represents a challenge perhaps unseen in the free agency era. It’s quite possible that he could reel off years as good for a decade. On the other hand, this is the first time he’s played at anything near this level. Some team could sign him to a $100 million contract and get the next Mike Schmidt; they could also get the next Larry Parrish.

I think he’ll be closer to Schmidt. Beltre’s OPS, expressed as a percentage of the league average, is 139. If he keeps this up through the end of the season – and he’s been playing his best ball of the year over the last few weeks – that would be the second-highest figure of the postwar era for a 25-year-old third baseman.

Of the 10 postwar players who had the most comparable offensive seasons to the one Beltre is having, six are of Hall of Fame caliber and the rest all had good careers after their age-25 season save Jim Ray Hart, a fine player who injured his shoulder in 1969 and was never the same again. The only one who stands out as a fluke, and the comparison that should most worry anyone thinking about signing a fat check made out to Beltre, is Larry Parrish.

Parrish – who briefly managed the Detroit Tigers in 1998 and 1999 – came up to the majors in 1974 as a 20-year-old third baseman for the Montreal Expos. He had the worst preage-25 career of the names on the accompanying chart; his OPS rate relative to his league’s was .98. (Beltre’s, before this year, was .96.) While Parrish had a great 1979, it was a fluke; he spent several more years as a solid player, but was never again a star.

What Beltre has going for him that Parrish didn’t is defense. Actually, he has that on almost every player on this list. Jim Thome and Dick Allen, both poor third basemen, made adequate first basemen; Bill Madlock was a notoriously bad defensive player, and with the exceptions of Schmidt and Santo, every other player on the list was mediocre in the field.

Beltre, though, would probably make a decent shortstop. He has tremendous range to either side, great instinct for where the ball is going, and a powerful arm. Some studies suggest that good defensive players tend to age better than poor ones. That’s a point in Beltre’s favor, as is the fact that his great offensive season seems to be the result of a new approach at the plate. His biggest weakness for years was his tendency to try to pull the outside pitch, but he’s now learned how to go with the pitch, and has developed awesome opposite-field power.

The historical precedents for players with the amount of major league experience Beltre has at his age are incredibly encouraging. So are the precedents for players of his age and position having the kind of season he’s enjoying.

He’s notoriously tough, having played a full season after a botched appendectomy and this one with a badly injured ankle. He’s handled failure and the pressure of high expectations and succeeded. There’s just not much to dislike about Beltre.

Sometimes teams have to take risks. There is a chance that Adrian Beltre is having a career year, and that next season he’ll turn back into a league-average hitter who plays excellent defense. I think it far more likely he’s established himself as one of the elite players in all of baseball. The Dodgers would be wise to re-sign him; the Yankees would be wiser to put Carlos Beltran out of their minds, reminding themselves that their current third baseman can handle shortstop and that their current shortstop would probably make a fine centerfielder.