Well IMO only a handful can close with consistency and durability because you do not only need good stuff but temper and balls as well. A lot of pressure is out there when the last inning comes around specially against tough line ups and close games. IMO closers are the master pieces in rosters, since they guarantee a win if you are winning after 8 innings, and could make the difference when you want to win it all... look at Koji and Pap, but that's me .