Is Alex Rodriguez the best third baseman in New York?

That this is a question even worth thinking about is an enormous testament to how good the Mets’ David Wright is. With the possible exception of Florida’s Miguel Cabrera, there isn’t a more valuable commodity in the game, taking salaries into account. Even leaving money out of the equation, the only player in baseball you’d rather have over the next five years is Albert Pujols. Wright is the best player on a team featuring Pedro Martinez, Carlos Beltran, Carlos Delgado, and Billy Wagner, and he turned 23 two months ago.

Still, asking whether he’s better than Rodriguez (or, to be more precise, whether he’s likely to be better than A-Rod this year, and over the next few years) doesn’t necessarily seem like a fair question.

Rodriguez, after all, has been the AL MVP in two out of the last three years, and, more important, has been the best player in the league five years out of the last six. He’s only 30, has missed all of six games this millennium, and is coming off the best offensive season of his life.

Wright has hit 89 home runs in his professional career; Rodriguez has hit 87 home runs as a Yankee. All this being so, I wouldn’t be surprised if Wright was the better player this year. I’m not expecting it – Rodriguez is a historically great player, one of the most unusual in baseball history, and not to be underestimated. But Wright is a lot better than even most fervent admirers seem to realize (I’ve been saying this since he was in Double-A, and it remains true), and Rodriguez is going to have a much more difficult time sustaining his production than you might think.

The case for Wright actually begins with a bit of a negative, which is that he’s not likely to get all that much better than he is now. Most people tend to think ballplayers all age in roughly the same way, so that someone who hits .310 at 22 should hit .340 at 27. For ballplayers as a population, this is true; for individuals, it isn’t. What separates Wright from most players his age isn’t just his unusually broad base of skills – he’s well above average in every phase of the game save avoiding strikeouts – but how mature he is.

Most players develop rapidly in their mid-20s because they learn how to play baseball. Wright already knows when to take a pitch and when to swing, when to pull and when to hit to the opposite field, and so on. There’s maybe a 25% chance he could take another huge leap forward and become a hitter of Rodriguez’s class, but the most likely case is that he’ll make small refinements and be about as good as he is now, perhaps a bit better, through his 20s.

The flipside is that there’s very little chance that, barring injury, Wright is going to be much worse than he is now, because his success is grounded as much in the way he applies his talent – his approach to and knowledge of the game – as in his talent. He’s the exact opposite of an Alfonso Soriano type, and that bodes well for the future.

So, we know what kind of player Wright is going to be for the foreseeable future – he’ll hit .310 AVG/.390 OBA/.560 SLG with 20 steals and good defense. This is what Rodriguez did in his first season as a Yankee, which was one of the worst of his career. So why should Wright be better than A-Rod?

The answer is that Rodriguez is 30 and has taken a pounding. Last year, I wrote a column in which I suggested the Yankees should think about moving their MVP to first base as soon as this year, and I stand by it. A-Rod belongs to two unusual groups: great-hitting shortstops, and players who were great before they could buy a drink.

Neither group ages well. Think about the shortstops: Cal Ripken had his last great year at 30, and immediately thereafter began consistently hitting about 10% below league average. Ernie Banks became a first baseman at 31. Alan Trammell, one of the most durable players in the league in his 20s,averaged 106 games a year from ages 30 to 35.

As to players who were great exceptionally young, Eddie Matthews hit 399 home runs by the time he was 30, 113 after. Ken Griffey Jr. has had one healthy season in his 30s. Mickey Mantle retired at 36. The reason shortstops and players who come up young age so quickly is that playing shortstop and playing as a big league regular at 20 are exceptionally brutal on the body. ARod has both going against him, which is a huge negative going forward. If he stays at third, a demanding position, he’s likely to continue the defensive decline that began last year, start missing more games, and lose offense.

Of course, if he moves to a less demanding position to preserve his health, he’ll lose a good deal of his value. As a first baseman he’d be one of the very best players in baseball, but not unique. If anyone can overcome these odds, it’s A-Rod, but chances are he won’t. Most likely, some flaw in his game – lessened offense, lessened defense, lessened durability, or some combination of the three – is going to emerge as soon as this year.

Meanwhile, Wright will just clip along, having the same season he had last year over and over again, probably having one year somewhere along the way where he’s as good as Rodriguez was last year. Given how consistent he’s been through his career, it’s an odd thing to say of him, but A-Rod is no longer a sure bet. Wright is as close to one as there is in baseball.

tmarchman@nysun.com