Rafael Palmeiro doesn’t know it, but he just ended his baseball career.

During a conversation with an arbitration panel, Palmeiro fingered a teammate as the source of a substance that may have triggered his positive test for steroids. I can’t even begin to explain what a bad idea this was. If this were the Mafia, Raffy the Rat would get whacked.

There is no question that Palmeiro is embarrassed, and likely harbors resentment for the teammate who let him down. But you don’t break the code, man. If you get caught cheating, you do your time and keep your mouth shut. Raffy, of all people, should know this. After all, his Cub teammates kept their mouths shut while he was banging Ryne Sandberg’s wife, so the story goes.

While he didn’t go out and say that the substance he obtained is directly responsible for his positive steroid test, he’s clearly trying to lay the groundwork for his defense that he’s an honest guy who trusted a dishonest person. But it’s a little late for that story. Had he kept his mouth shut, and taken his lumps, he would still have been accepted by the other players in the clubhouse, if not by the fans. By ratting out one of his teammates, he guaranteed that no one will ever want to play with him again.

Perhaps the most curious part of all is: who is this mysterious teammate? Conventional wisdom would suggest Sammy Sosa, but I honestly can’t imagine that Sosa would ever risk getting caught with any of that stuff, not after already suffering through a corked bat scandal, which many speculate was a result of no longer using steroids. So who is it, then? Is it a starter? What would the ramifications be if it turned out to be a stud like Miguel Tejada? Just how deep, and how widespread, is the steroids issue?

There was talk that Palmeiro planned to play the final week of the season. To that I say, Raffy, do yourself and the rest of the Orioles organization a huge favor and stay home. You don’t even want to know what’s waiting for you, and quite frankly, your teammates, even the one who gave you the juice, deserve better than that. And based on recent developments, the interim skipper for the O’s agrees. It’s sage advice, Raffy. I’d consider it.