Who can I trade BJ Upton for?

Good job on the Cain for Weathers deal. Take it before he changes his mind. I personally think Carpenter is useless for this season. I'd grab Dotel, who's soon to come off the DL, and will be KC's closer upon his return. Your offense will be good once guys like Texeira, Young and Soriano get into their groove. I'm not a big fan of Beltre or Chavez, so I'd keep Upton for 3B and try to trade off one of those guys. If you don't like Upton, I'd try to get Aramis Ramirez, who has yet to heat up and is in a great lineup. I don't think you necessarily need more closers, you'd still have 3 after trading Weathers (4 if you grab Dotel), but if you feel you do, then yes, Wagner is definitely a good one to go for.