Allow us to preface this by saying that we are not attempting to call into question the greatness of one Mariano Rivera, nor are we necessarily agreeing with the opinions of Halos Heaven. We are simply offering strong evidence that on one pitch in the ALCS Rivera may have thrown a spit ball. Which would be the same as Alex Rodriguez, for example, using a corked bat for one AB in the ALCS. In other words: Kind of a big deal. Draw your own conclusions with this evidence.

From SB Nation's Halos Heaven:

• With a tie game in the bottom of the 10th, the Yankees bring in Rivera.
• After warming up, he has his back to home plate so the home plate ump can't see.
• He looks down at the ball, then up to see if the 2nd base ump is watching.
• He then looks back at the ball and appears to spit on it.
• And when he tests clean for steroids they say he is not a cheater.

They even have some frame-by-frame screengrabs of the incident in question, and looking at them, it's pretty clear Rivera spits on the baseball. Plus, there's this video:

According to Baseball Reference, a spitball (which was made illegal in 1920) is "a pitch in which the pitcher applies saliva to the baseball, either to change its aerodynamic properties or to reduce friction between his fingers and the ball." Which would certainly explain the movement on Rivera's cutter.

I find it hard to believe that Mo has spent his whole career cheating, and no one noticed until yesterday. But for at least one pitch, it certainly looks like Rivera threw a spitball.