Nick Swisher NYY
Melvin Mora on the Baltimore Orioles is the only one that I know of.
In the 2009 MLB season, only Mariano Rivera of the New York Yankees wears #42.
Nelson Cruz (Texas Rangers)Todd Helton (Colorado Rockies)(please add to this list)
Drew stubs
alex rodriguez
Robin Yount - Milwaukee Brewers
9
Willie Mays, Robinson Cano, Trevor Plouffe.
Brett Favre
charles barkley
Shoaib Malik
football