Friend and author William Ryczek pointed out this article by Dave Smith about the use of closers in MLB over time. For ninth inning save situations. Here is the synopsis:

No one questions that relief pitcher usage has changed immensely in recent decades. If we are to believe managers and coaches, and (more importantly) the baseball media, today’s rigidly defined progression has contributed mightily to winning. A number of researchers have sought to determine whether the evidence bears out this anecdotal belief. None, until now, have unleashed the full power of Retrosheet’s database. Examining the last 95 years of game data, Dave Smith shows that the probability of victory when leading by 1-3 runs in the ninth inning has been remarkably constant the whole time, whether the starter goes the distance or the manager deploys a fresh “assigned role” reliever every inning from the sixth or seventh on, or any pattern in between.

And this is the money passage:

The average winning percentages over these years are 90.8 when a reliever starts the 9th inning and 91.2 when the same pitcher continues from the 8th, whether starter or reliever.

Smith’s conclusion is that the closer doesn’t matter, unless he is an elite closer (the team wins about 92% of the time with an elite closer).

My feeling, however, is that baseball evolves, and managers are much better at recognizing that evolution than fans believe. They are trying things every day, seeing what works and what doesn’t. In other words, the winning percentage may be constant over time because managers are constantly fighting to keep it the same by adapting new strategies. It’s possible that without the development of the modern bullpen, that winning percentage would be much lower.

It would be good to look at inflection points. How well did the Ron Davis/Rich Gossage do in these situations, or the Rick Honeycutt/Dennis Eckersley Athletics. If they are gaining an advantage with the setup/closer, then other teams are likely to adopt the strategy and even things out. The 2014 Royals might also be an inflection point, with the three inning, hard throwing bullpen.

One advantage of the move to more relievers is that team might get more mileage out of healthier pitchers. It does appear that pitchers go on the disabled list as much as ever, but we also know that shoulder injuries are almost non-existent thanks to better conditioning of the rotator cuff. I wanted to get a handle on how much pitchers are pitching, so I created a spreadsheet and chart. I use pitcher with at least 100 innings pitched in their careers. I basically wanted to eliminate the low talent. My feeling is that if a pitcher gets 100 innings, he was good enough to stick around for a lot of relief appearances or 15 or so starts. For every debut year, I looked at the average number of career innings for the group, and the average number of seasons pitched. If innings are going down, but seasons are going up, the trade-off might be worth it. I did this through 1997, since everyone from that season is probably retired. At the end, you do see seasons going up a bit as innings go down. It’s not a big difference, but it will be interesting to see how this trend plays out over time.