Uncharted: Golden Abyss is the first game in the series to release without multiplayer since the original, but possibly not for long. A purported screenshot from a glitch shows that you might be able to battle against your friends, though not in the way you'd expect. The image seems to indicate a collectible card game (CCG) style mode.
A post on NeoGAF (via Push Square) shows a card with number stats, and refers to Fortune cards and Artifacts. The indicators appear to point towards a CCG as downloadable content, which would align with a recent comment promising "something different" for Uncharted multiplayer.
The user who claims to have found the shot says his game froze on the image. It does seem odd that a teaser image would even be present in the game, but stranger things have happened. Either way, take it with a grain of salt until we get official confirmation. Shacknews has contacted Sony Bend regarding the rumor, and will update as more information becomes available.