I can't see Owen, Morientes, or Saviola for that matter coming to Juve just to be a 4th striker.
Their talents are superior to that of your normal 4th striker, and they wouldn't, or shouldn't have to accept such a role.
Either you get one of two types of players for that position.
1) a young, and I'm talking an 18 or 19 year old player, with the exception of Rooney, who is willing to watch and learn for the most part, and play in some Coppa matches and first round CL matches.
2) A veteran who may be past his prime, but would be willing to take a reduced role for a chance to play on a winning squad.