Update: Gagne says he didn't do it.

The official site has this:

Mariano Rivera's save against the Red Sox on Sunday night was harrowing enough in its own right. Little did the Yankees know that their closer was bothered by a finger injury throughout it all.

Rivera was clipped by a stray baseball from the Red Sox bullpen on Sunday, startling him while he was stretching during the eighth inning. The ball struck his interlocked hands and robbed him of all sensation in his right pinkie finger just prior to his entrance into a two-run game.

"That thing was numb," Rivera said. "I didn't have feeling for the whole game."

Now, thankfully, Mo appears to be fine. Who threw the baseball, you ask? Peter Abraham says it was Eric Gagne. After hearing this, my research led me to this photo of what appears to be Gagne practicing for the opportunity.

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(Seriously, though, someone needs to raise the wall or throw in another direction. I would have thrown my body in front of that ball, had I been standing in the Yankees bullpen).