I have no idea what they would do, I don't think it would Urruti, as he doesn't occupy near enough salary or a DP spot, given that, it'd most likely be Adi whom does. They'll have to do a lot of juggling to accommodate Altidore.
There are also rumours of clubs being allowed a 4th DP spot this year as well, I think eventually they want to put it to 5. Making all this frivolous puzzle piecing redundant.