The Yankees signed reliever Rafael Soriano on Thursday, a move general manager Brian Cashman vetoed, according to a source. Cashman was overruled by co-owners Hank and Hal Steinbrenner. Last week, Cashman said he wouldn't give up a first-round pick to sign a Type-A free agent such as Soriano. Before the Soriano signing, Joba Chamberlain was going to be the eighth inning bridge to closer Mariano Rivera.