In 2011, Papelbon struck out more than 12 batters per 9 innings, not to mention posting an 8.7 K/BB ratio.
Here are all the pitchers in history to post a 12 K/9 season, minimum 40 IP, in their Age 30 season:
This never happened before 1995 because K rates just weren't high enough in MLB.
Let's take a look at how these pitchers did following their Age 30 seasons.
- Grant Balfour followed his great 2008 with an inexplicably bad 2009 but has rebounded with strong seasons in 2010 and 2011--he's also one of only two guys on this list not to suffer a serious injury after his Age 30 season.
- Joe Nathan was really good in 2005 and then was great in the 4 seasons following. But then he missed all of 2010 due to injury and was not good in his 2011 return.
- Octavio Dotel was good in 2004 but then suffered significant injuries in each of the next 3 seasons. In the last 4 seasons, he's ranged from decent to good.
- Rob Nenn had his best season in 2000 and then declined each of the 2 following seasons as his K rate dropped and his hit rate soared. Then he hurt his arm and never pitched again after 2002.
- Roberto Hernandez did the best out of this group, taking off the year after his Age 30 season and posting 7 straight seasons ranging from good to great.Then he pitched 5 more seasons from Age 38 to Age 42, and pitched pretty well in most of them.
The bottom line? Significant injuries happen to relievers, and they happen quite often.
I'm also suspicious of Papelbon. He went all of 2011 without causing a single on-field or off-field problem, but that was the first season of his career in which he achieved that. He also posted amazing and consistent numbers, coming as he approached free agency for the first time. Did he grow up? Maybe--but it seems more likely that he just knew he had to behave and perform to cash in. Now that he's got a massive 4-year contract, I'm skeptical that he'll continue to try as hard in any capacity.