All three teams have young guys here and the Yankees could very well go with somebody different from who I put here. However, I think that Brett is the best option and will get the Opening Day start.
Yankees- Brett Gardner- It looks like Brett has won the job with his superior defense and speed. He's also hit much better than Melky this spring. I`m not expecting great things out of Gardner though. I very much doubt he'll ever be much more than a borderline starter. With his speed and defense though, if he can get on base at a decent clip he'll be a solid player for them. If he doesn't hit watch for Swisher or Damon to take his place.
Red Sox- Jacoby Ellsbury- I'm not a prospect expert but the consensus seems to be that Ellsbury is a much better prospect than Gardner. Boston was confident enough in his abilities to trade away Coco Crisp for a reliever. Last year was his first full year in the majors and he hit fairly well. An EQA of .264 is fine for a guy who's defense is outstanding and can steal at the rate he can. He also is a candidate to get better at only 24 years old.
Rays- B. J. Upton- Upton is one of the best young players in the game. However, he's often overshadowed by the other young guys on the Rays. He's far and away the best hitting centerfielder in the AL East. He put up an EQA of .312 two years ago and last year it was .291. Not only that but he's a solidly above average fielder. He's not quite as good as Ellsbury or Gardner but he's still good. Another scary guy who could still get better on the Rays.
Conclusion- Rays- Red Sox- Yankees- This one was pretty easy for me. Upton is already a star and hasn't even hit his peak years yet. He's the total package. I pretty much went with Ellsbury over Gardner based on their reputations. Gardner is an interesting player though. His style of play is exciting and if he can get on base he's going to be an exciting player.