Former Twins' manager Tom Kelly was a crank, but he always stressed the psychological value of having a strong closer. A lot of folks don't put much stock in the "between the ears" part of the game, but you watch a team with a shaky closer and often times, they get out of sync trying to put games away. You want to hand the ball to a guy and have thew team know full well that if the lead isn't held, it's an aberration and not a portent.