I recently wrote about teams no longer paying a premium to land closers with 9th inning experience, instead choosing to spend less and acquire very good relievers with little 9th inning experience. It seems teams have moved away from the conventional thinking that a closer must have experience or a special mentality in order to succeed as a closer. This made me wonder whether the view that a closer must have to throw hard was still alive. It is important to note that throwing harder certainly gives the pitcher an advantage, but it is also very possible to succeed without being among the hardest throwers. In order to look at this, I looked at all Relief Pitchers with at least 10 saves from 2010-2013 and separated them into two groups based on their average fastball velocity (aFV), based on P/Fx. The aFV for the entire group of 93 pitchers was 93.0. I chose 93 as the divider between High Velocity (HVelo) closers and Low Velocity (LVelo) closers.
Looking at the breakdown of the two groups, the HVelo group included 53 relief pitchers and the LVelo group included 40 relief pitchers. The difference of 13 pitchers between the groups should not affect the results too much, as the sample is big enough to negate this discrepancy. However, the difference does say something about closers during this period, as there were many more hard-throwing closers than low velocity closers. Looking into the numbers between these two groups for this 4-year period, it is clear that the HVelo pitchers were more effective. They averaged 15 more saves over that period and outperformed the LVelo pitchers in every statistic, except BB/9 and BABIP. LVelo pitchers walking less batters per 9 innings is not surprising, as they usually have better command in order to compensate for less strikeouts. HVelo closers were also better at fulfilling their role, as they had a 81.7% conversion rate, while LVelo closers converted just 77.5% of their opportunities. If you look at this four-year window it is clear that the harder throwing closers have been more successful and there have also been many more hard-throwers used in the 9th inning than LVelo relievers.
However, if we take a look at just the final year of this four-year period, we see something different. Looking only at 2013 and relief pitchers that had at least 10 saves, I broke the pitchers into two groups using the same criteria as before: HVelo is all pitchers with aFV higher than 93 mph and LVelo is all pitchers with aFV below 93 mph. This is the same cutoff as for the four-year period because the mean is relatively unchanged, at 92.8. Unlike from 2010-2013, these two groups were essentially even: of the 37 qualified pitchers, 19 were in the HVelo group and 18 were in the LVelo group. This alone shows that teams are more comfortable using effective relievers in the 9th inning, even if they do not light up the radar gun. Just using more LVelo pitchers does not actually prove they are as effective or better than HVelo relievers, but it does show teams may be moving away from the conventional belief that closers must throw hard. When I looked at the numbers of these two groups, I saw evidence that the LVelo group was certainly as effective, if not more effective, than the HVelo group. The HVelo group saved just one game more on average; however, their save percentage was 87, compared to the 88.7% of the LVelo group. Just as before, the LVelo outperformed the HVelo group in BB/9 and BABIP, but they also had a better average ERA than the HVelo group. While the HVelo pitchers had a much higher K/9 (10.7 vs. 8.4) and a better HR/9, the LVelo group did a better job at preventing runs and also a slightly better job at converting their save opportunities.
Certainly, looking at just one season is not a very large sample, but I believe last season was the beginning of a trend. The role of the closer has evolved quite a bit in recent years and many long-held beliefs are being dispelled. I believe teams have realized that a pitcher does not have to be the hardest thrower in the bullpen, instead he just needs to be the most effective. In 2013, both teams that reached the World Series turned to closers without previous experience and who were both among the LVelo group. The Cardinals chose to give Edward Mujica the closer’s role, instead of turning to young flamethrower, Trevor Rosenthal. Mujica turned in a fantastic season with 37 saves and a 2.78 ERA. The Red Sox also entrusted their 9th inning duties to a member of the LVelo group, Koji Uehara. Uehara took over as closer after both of the Red Sox’s other options suffered season-ending injuries, but Uehara still totaled 21 saves and a 1.09 ERA. Both these closers overcame common beliefs that closers need experience in the 9th inning to succeed and must also throw hard.
* I would have liked to look at a larger sample than 2010-2013, but I did not feel comfortable using Pitchf/x data older than 2010. Since its inception in 2006, Pitchf/x has vastly improved and become much more accurate.