The Yankees have had serious discussions with the Rangers about reliever Eric Gagne, two major-league sources confirmed Friday night. Gagne is closing for the Rangers but would be a setup man for Mariano Rivera if he were to come to the Yankees. If the Yankees could add Gagne, the back end of their bullpen would be hugely upgraded. The teams have not been able to agree on a return for Gagne but can continue to haggle over players until the 4 p.m. Tuesday non-waiver trade deadline. The Rangers want pitching in return and have interest in minor-league righthanders Ian Kennedy and Jeffrey Marquez. They also like centerfielder Melky Cabrera, but the Yankees are unlikely to surrender him for Gagne.