Alright; here's what happened ... the 5 and 48 cars slowed down to hit pit road, Carl was comin' like a bat outta hell, and had nowhere to go but to the left of them, then hauled ass around them and back out in front of them and onto the track. While he
didn't hit the commit line, he pretty much was in the area for going to pit road, and probably should have just proceeded down pit road instead of cutting back out. The reason I say that is because with the limited visibility right/left that drivers have, he wouldn't have known that it was clear for him to do that, and I don't think his spotter told him "Hey, you're clear, jump back out onto the track."
As much as it sucks, technically, he DID pass below the yellow b/c neither Johnson nor Busch had passed the commit line either, even though he lost positions in the process. But had JJ or Busch (who is the LAST person I'd defend) decided to not hit pit road, he'd have gained position on them.