It's not often that you see a runner on first base arguing with the first-base umpire. But that's exactly what happened in the bottom of the sixth inning at Wrigley Field today, as Casey Blake got into it with crew chief John Hirschbeck.

I was watching the Cubs' broadcast, and Len Kasper and Bob Brenly both were perplexed.

Just a moment later, though, I saw this on Twitter, from C.J. Nitkowski: "Watching some daytime MLB. Camera just zoomed in & didn't realize it caught a pitcher cheating. Don't ask me who/what. Tricks of the trade."

Still a mystery, right? Then, this: "Uh-oh Casey Blake is on to it. TV guys completely in the dark. I should start my analyst career."

Nitkowski said he wouldn't tell us the who/what ... But with the mention of Casey Blake, we know the "who" must be Ted Lilly.

Still no what, though. And the broadcasters never revisited the subject (and even if they'd figured it out, they're probably not going to score a lot of points in the organization by exposing one of their own guys as a cheater).

Fortunately, the Twitterverse is vast and powerful.

First, this from GreenLantern411: "pretty sure CJ is talking about lilly's left foot being nowhere near the rubber ... was pretty blatant"

And a few moments later, this from (Rangers fan) jcooksey04: "Lilly's foot was about 6 inches from the rubber in his last start vs the Rangers. Umps never saw it."

Thus armed, I went back and watched the bottom of the sixth inning again, but this time the Dodger broadcast with Steve Lyons and Eric Collins.

The fun begins with two outs and Blake on first base. Reed Johnson fouls off one pitch, then another. Blake, leading off, is one of the two people in Chicago with the best look at whatever Lilly's doing (first baseman Derrek Lee is the other). Before throwing his third pitch, Lilly steps off the mound. We don't know why. A moment later, he steps off again and finally we see Blake standing on first base, complaining to John Hirschbeck about something.

Lyons says, "I think Casey Blake maybe thought he saw a balk, and he's over there chipping at the first-base umpire about, why aren't we calling it?"

First-base coach Mariano Duncan gets between Blake and Hirschbeck, and eventually Joe Torre saunters out for a bit of mid-afternoon entertainment.

Finally, a replay from the high-third-base camera, showing Lilly getting set, and Blake just standing on first base and pointing at Lilly. And now Lyons gets it: "Take a good look at Casey. And he's trying to say whether or not, maybe Ted Lilly isn't even on the rubber. We've talked a lot about the fact that he stays way on one side of the rubber or the other, and Casey's saying he's about four inches off the rubber in front of it. Which can give you a significant advantage."

What we'd missed the first time around -- and what the Cubs broadcast somehow never managed (or bothered) to show -- was Blake turning to Hirschbeck and holding his hands four to six inches apart. And again, if anybody would have known, he would.

Torre didn't belabor the point, Reed Johnson made out on the next pitch, and Lilly cruised through the seventh inning. This is a small thing. Pitchers have been cheating in exactly this way since pitching rubbers were first installed, I'm absolutely sure. But you may, if you like, apportion extra credit this afternoon to Casey Blake, to C.J. Nitkowski, and to the InterWeb.