It’s impossible not to feel for Cincinnati’s Ken Griffey Jr. Somewhat healthy for the first time in five years, he showed this season that when his body will let him take the field, he still ranks among the elite hitters in the game. He also showed that he will never be healthy again.

Griffey, 35, is scheduled to have two separate surgeries tomorrow – one to clean out a knee that has been bothering him for years, the other to clear scar tissue out from around the torn hamstring he had bolted into place with titanium screws last off-season, a rare procedure that could have ended his career had it not gone well. Neither of these maladies, it should be noted, are what ended his season – that was a sprained foot.

We hear about such problems so often that it’s easy to give them no thought, and usually the full reality of what an athlete is dealing with doesn’t even settle in one’s mind. I can put it this way: Two years ago, when I was 25 and in good shape, working out three times a week, I slipped on my staircase and tore my anterior cruciate ligament in the most minor way possible, which required me to wear an immobilizing knee brace for a while. This sort of injury, which wouldn’t take a pro athlete off the field in a game, left me unable to bend my knee for days without howling like a child and muttering to every one of my friends about how I couldn’t do this or that because I’d “torn my ACL.”

Griffey has been playing for three years with a knee problem that actually required surgery, and slugged .576 this year while playing on a hamstring that had literally been torn in half and which required, again, three titanium bolts just to anchor it to the bone.

While it’s hard not to wonder what Griffey might have done in his career had his body not fallen apart once he turned 30, the truth is that his injuries are probably just part and parcel of his greatness. Of the players Griffey most resembled historically before his spate of injuries began, very few did much in their 30s. Duke Snider never played anything close to a full slate of games after he was 29.Mickey Mantle only did so because the Yankees would frequently pull him out of games after a couple of at-bats, and even then he was out of baseball at 37. Eddie Matthews was done as an elite player at 33, and retired at 37; Jimmie Foxx was more or less completely done at 33.

There are exceptions like Frank Robinson and Al Kaline, but for the most part players who have the kind of success Griffey did at an early age burn out early, most likely because of the pounding their bodies take while still developing.

In retrospect, Griffey – who played center field, a position that’s brutal on the knees, and did it on AstroTurf for a decade – seems to have been an obvious candidate for this kind of collapse, and in truth the unusual thing is that he’s playing at all.

This brings me around to Griffey’s former teammate, Alex Rodriguez, who turned 30 in late July, has spent the majority of his career at a defensive position even more demanding than center field, and who is a better player than Griffey ever was. This year has been perhaps the finest of his career – it’s also seen him notably decline in athleticism. What set Rodriguez apart for years was that he hit like Albert Pujols while being a Gold Glove shortstop and a top baserunner; he now hits like Pujols while being a below average defender at third and a baserunner whose best attribute is his headiness rather than his speed.

Part of this is because Rodriguez has bulked up, and the tradeoff between better offense and worse defense is probably one worth making. As Griffey, Mantle, Matthews, and the rest show, though, Rodriguez is heading into a very perilous time in his career, when the wear and tear of a decade of baseball may well start wearing on him. I would argue that his loss of athleticism shows that it already is.

Going forward, the Yankees have to start thinking about this in realistic terms. Rodriguez has the bat to be a perennial MVP candidate at any position including first base or left field, where the day-to-day demands on his body would be less, possibly enough so to allow him to maintain his value into his 30s in a way his predecessors did not. If Rodriguez stays relatively healthy and keeps swinging the bat the way he has this year, he’ll have approximately 640 home runs by the time he reaches Griffey’s age.

In 2000 (and, insanely, even this year) no one wanted to think about Griffey’s talents being wasted at first base or even left field. But a talent that can’t be used may as well not exist at all.

tmarchman@nysun.com