I'd shy away from using a current player's name... say you call him "Manny", then in 2009 when Manny is a Yankee (after the Sox don't exercise his option years), you will be forced to kill your own dog. That would be very sad for you and the kids, although not as sad as having a dog named after a Yankee.
Try "Yaz" or "Teddy" or some such if you want a player's name!
- Frank