Yankees closer Mariano Rivera isn't concerned about pitching at age 40 in the final year of his contract. "Take it a year at a time and see what happens," Rivera said Thursday. "See how things go, how things develop and go from there." He doesn't know how many more years he wants to pitch but says, "I still think I can perform." Rivera went 3-3 with 44 saves in 66 games last season, helping the Yankees win their first World Series championship since 2000.