Most saves of more than one inning (since 1994):
1. Mariano Rivera, 116
2. Keith Foulke, 55
3. Trevor Hoffman, 52
4. Danny Graves, 49
5. Jason Isringhausen, 42

Still, questions persist: Why are closers so limited? Why do they almost exclusively pitch one inning? Is it because, after much study and observation, everyone in the game realized that one-inning closers are more effective at holding leads than multiple-inning guys? Maybe, but I doubt it. The numbers I've seen strongly suggest that teams are blowing late-inning leads at exactly the same rate they did in the the 1980s and the 1970s and the 1950s and so on. Is it because hitters are so much better and the only way to counter that improvement is with a one-inning closer?

Joe Posnanski @Joe Blogs