Not the worst call of the year. While I agree the play was made, Cuddyer made absolutely no effort to sell the tag, and from the umpire's angle, there was no tag -- just Cuddyer flipping his glove at Shoppach's stomach.
I thought the call was correct until I saw the MLB Network broadcast and you can see Cuddyer's glove bend just a bit -- and I'm still not completely convinced.
What shocks me as an umpire is a guy making that sort of call with the ball there so far in advance. It's the same as the phantom foot on the bag turning the double play at second -- as an ump, you're pretty damned sure the guy DIDN'T touch the bag, but are you really sure enough to call the runner safe?
It's also interesting that at the end of that video, you can see Marquez start to call Shoppach out, then reverse himself. I know people will think Shoppach's claiming he wasn't tagged caused the flip, but it's just as likely Marquez started to punch the runner out and then realized, "Hey, I never saw a tag."