For nearly two decades, the Yankees enjoyed immense comfort in knowing that the greatest closer of all time was standing by in the bullpen, waiting for the opportunity to enter the game late and help the team nail down a win. Year after year, management went to great lengths to surround him with a supporting cast of outstanding setup men, all tasked with the singular responsibility of getting the ball to Mo. Once Mariano Rivera retired, talk among fans immediately shifted from celebrating the game’s greatest reliever to discussing how the club could build the best bullpen.