In the end, it came down to money for Pedro Martinez.

You can hardly blame him – or the Red Sox.

Professional sports, no matter how loyal the fans or how sincere the admiration for a superstar, is about making money.

We shouldn’t be surprised that Martinez opted for a four-year deal worth more than $50 million from the New York Mets. The best the Red Sox offered was a three-year, $40.5 million deal. The extra year – and the extra money – was the enticement Martinez needed to end his time in Boston.

A pitcher of Martinez’s caliber will be missed. He’s a surefire Hall of Famer, who lured a new generation of Sox fans to Fenway. But that time is up.

Martinez is 33 years old. A four-year contract would keep him with the Mets until he’s 38, old for a Major League pitcher. The Red Sox refused to gamble that Martinez, who has already had arm surgery, would still be an asset that far down the road. It’s probably the right business decision, even if it leaves a sick feeling in the pit of our stomach.

Martinez is leaving a World Series champion team and a perennial contender. He’ll join a struggling Mets franchise, which has finished last in the NL East in two out of the last three years. This year, the team finished 20 games under .500. Martinez will have his work cut out for him in a league where he’ll have to bat.

We’re sad to see Martinez leave Boston, but business is business.