On Tuesday, Sammy Sosa of the Chicago Cubs took an at-bat with a corked bat. We know that because the bat broke and the cork was there for the world to see. Altering a bat, corking included, is illegal under Major League Baseball rules.

Sosa admitted it was his bat, but said he intended to use it only during batting practice, “to put on a show for the fans.”

That would indicate Sosa felt hitting home runs during batting practice off lollypop pitches required a corked bat to “put on a show.” Stated otherwise, he believed his own natural ability combined with legal bats would not result in sufficient power to be fan-worthy.

Interesting.

All of Sosa’s other bats were confiscated from his locker by MLB innings after the incident. They were found not to have cork. The MRI examination was not public. It should have been.

The discovery of weapons of mass destruction is difficult enough without having to worry about an MLB cover-up.

Cubs manager Dusty Baker, a friend whom I respect, said Sosa should be considered innocent until proven guilty. Dusty, I know you will go to the ends of the earth to stand up for your players, but let us talk about the smoking gun rule here.

Some sports media members are already sarcastically sneering at those who dare to believe playing by the rules matters. It does.

Tarnished is the word that seems applicable, again, and it’s a shame. We know that Mark McGwire used supplements that contained steroids in his record-breaking home run years, years in which he battled against Sosa. The supplements were not illegal. The fan wincing is real.

Sosa’s intimation that he has corked bats, but uses them only for batting practice, causes your head to ache and his credibility to snap.

To the best of our knowledge, Hank Aaron, Babe Ruth, Ted Williams, and others of those eras did not use enhancements to increase their bat power. If anything, a few sluggers during those decades were hitting dingers with old-fashioned hangovers that should have decreased their ability to drive the ball.

What Sosa has done, as did McGwire, is to create a mental asterisk next to his home run totals. If Sosa cares, he will have every bat publicly checked through the rest of his career.

McGwire, Sosa, and others in today’s game know what adds the extra zeros to their paychecks: the long ball. More than one player has privately said that if that means using legal or illegal drugs or corked bats to get there, so be it.

Too bad.

In Sosa’s case, at least for that one at bat last week, his at-bat was illegal. Period. Did he mistakenly take his practice bat to the plate? Does it really matter?

If he thought he needed a corked bat to entertain the fans prior to the game, every reasonable brain cell says he must have felt the same way about hitting home runs during the game.

This is about playing within the rules. That still matters. Sosa cheated. He cheated the game. He cheated the fans. He cheated his team. He cheated himself. It matters.

There is no satisfaction in this for anyone, but the rules and the integrity of the game are more important than Sosa.

It is said of baseball players that they are to give the fans a chance to dream. Dreaming of cheating is a nightmare. Accepting cheating is a sin.

Old Town native Gary Thorne is an ESPN and NBC sportscaster.