If he really does leave just so he can try and play in the WC next year, fine let him go. Its really arrogant and short-sighted of him to think that moving to UTD will increase his chances that much of playing in Brazil.
How he thinks that in a year's time he will be able to replace either Xavi, Iniesta, Mata, Silva, Santi and Xabi is beyond me. He just needs to realize that his time will come in the next WC, just not yet. If anything, the player he should be trying to beat out in that squad is Xavi and what better place to do that by replacing him at the club he plays at?
I really don't understand his M/O in all of this and why he thinks (maybe) starting at UTD will magically want Del Bosque to pick him. Again, he still has a lot of competition at UTD since they will most likely only play with two CMs so its no guarantee he will start there, either.
I hope he stays, nothing concrete has come out yet but Tito, Rosell and Co. REALLY need to guarantee him more starts. He does deserve that, but a spot on the NT is a whole new story.