If Battlefield 3 is out of the picture then that just leaves Theif 4, Half Life and TES right? Are there any other games that could possibly be the cover? I certainly can not think of any more.
Well Thief 4 was also officially announced, though no information or details were given so it wasn't quite "revealed". However, it doesn't have much potential to be the cover.
@Mr. Tissue Box: Yes, yes. Sorry about the confusion between announced and revealed. The possibilites remain, but the chances are low to these games.
It could be the new TimeSplitters game by Crytek. I don't know if it was formally announced. But certainly it wasn't revealed.
"As of 17 August 2009, the project has officially been declared as on hold. In a recent interview, Crytek UK claimed that they would continue the project once there is a high industry demand for such a game." - Wikipedia article on TimeSplitters 4.