dodgers-giants-lincecum out

[so cal lurker]

I was at the dodgers-giants game and was hoping someone here saw and could explain the play on witch Lincecum was called out at third after the play.

What *appeared* to happen: Lincecum at 2nd; another runner at firs. Fly ball down the left field line. The outfielder's play was out of my line of vision, but judging from the players' reactions it was unclear to them whether or not he caught it or if it was a fly ball. Throw came in to the middle infielders as Lincecum ran back towards second. Throw is made to 1st [perhaps because they thought the fly was caught and were going for a double play?], and U there seemed to signal an out. Lincecum went back to third. Dodgers talk to the umpires; umpires huddle; one of the umpires then points at Lincecum and signals him out. (I believe he also tapped himself on the chest with both hands before or after signaling the out.) During the play, I don't believe the ball ever got near Lincecum.

We were perplexed (and of course they did not show a replay). Was Lincecum called out for running backwards? Was the chest tapping some sort of interference/obstruction signal? Was there an umpire misinformation of some sort and they "made it right" by calling Lincecum out? Seemed a very odd play, but perhaps I missed something obvious -- I couldn't find anything on the web discussing the play, but since it was a blow out, it is of course of purely academic interest.

thx