I think Yankees really commit to reduce their payroll to certain level which I agree with. Even though I don't think Yankees really need to deal one of outfielders because Swisher can play a lot of positions, I think Yankees will trade one of them if the right deal is out there. Because I think Yankees will and should get another veteran starter by trade or free agency, they probably want to free some payroll for that starter and use rest of budget to get a center fielder.
Based on what I heard from Yankees and what I saw from watching Yankees games, I think Yankees will deal Nady that I agree with.
Cashman already said Damon is not going anywhere because he is our lead off man. Matsui certainly can produce well when he is healthy. Not to mention it's very difficult to trade him based on his situation. Because of Japanese market, I don't think Yankees will be willing to risk the possibility of hurting Japanese market by trading Matsui. It's totally different story to trade him now instead of letting him walk at the end of his contract.
Swisher has a bad 2008 season which may result from luck, new team, new position and new batting order. I think he will be back to his 2006-2007 form. Not to mention Swisher is a patient switch hitter who can play a lot of positions and sign a team friendly contract. If Yankees let Damon and Matsui leave after 2009 season, it will be good to have him for one of spots. For me, I also like his personality. I think he will be good for Yankees.
On the other hand, Nady has a career year which will get paid much more in Arbitration. Don't forget Yankees try to control their payroll now. Of course, no one says Nady can't repeat that performance. Even if Nady's agent Boras let him hit the free agent market and sign with other teams, Yankees certainly can get draft pick for him if he perform well again in 2009 season. Don't forget Yankees still can sign him if he perform well again in 2009 season even if we trade him now. However, you always want to trade players when their values are high and buy players when their values are low. Based on what I saw from him and Swisher last year, I will bet on Swisher to perform better than Nady in 2009.
Of course, this all depends what kind of deals Yankees can get for them on trade market.