What's wrong with Fernando Rodney?

Recently, a friend of mine asked me on twitter what I thought about Fernando Rodney. Within the confines of a character limit, I couldn't hem nor haw, so I had to face the fact that I didn't know what to think. He's one of those outlier cases that makes baseball interesting. Here, to the best of my ability, are all of the facts that should be considered before forming an opinion on Rodney.

1. Fernando Rodney was an undeniably talented but frustrating reliever for most of his career. He always struck out around 20% of the batters he's faced, but he also walked a bit over 10%. This, along with the promise of his stuff, was good enough to keep him near the back end of the Detroit and Los Angeles bullpens, but not good enough to make him a true relief ace.
2. In 2011, Fernando Rodney was really bad. His strikeout rate had declined over the past few years to below 18%, but that year, his walk rate rose to nearly 19%. Those are the type of numbers that lose you your job.
3. In 2012, Fernando Rodney signed with the Rays and instantly became arguably the best closer in the league. He set the single season relief ERA record, and posted the peripherals to support it, striking out 27% of the batters he faced, and walking only 5%. Michael Valencius made a nice graph comparing the three periods of Rodney's career.That is a turnaround, at age 35, that defies statistical probability and is quite difficult to explain. Still, there were attempts made to explain it.
4. Explanation one: Pitch usage. Back when Rodney was first signed, I proposed that the Rays would simply ask him to throw his best pitch (his changeup) more. He did. In fact, he threw it an extra 10% of the time and completely scrapped his slider to become a two pitch pitcher, to great effect.
5. Explanation two: Starting spot on the rubber. R.J. Anderson and Jason Collette both noticed this. The Rays changed where Rodney pitched from moving him to the other side of the rubber.
6. I like these explanations for why Fernando suddenly became great. They feel right. But that doesn't change the fact that Rodney is a reliever who late in his career suddenly became great. That's a troubling player to have on your team, because any projection system that uses aging curves and regression to the mean is going to disbelieve, and however smart we analysts may think we are, regression to the mean is more often than not smarter. The systems had Rodney pegged for a low to mid 3s FIP in 2013. That's still good, but not great.
7. In reality, Rodney has been worse than that, but in an interesting way. He's walking even more batters than he did in the bad 2011 (19%), but he's also striking out more than he did in the good 2012 (29%). This is an extreme shift, and it's very specific, rather than a general move towards good or bad. Rodney's problems are 100% about walking batters, and a quick glance at the FanGraphs plate discipline numbers show that the culprit is nothing more mysterious than not throwing enough strikes. Once again, it's time for some explanations.
8. Explanation one: Pitch usage. He's throwing his changeup even more frequently (44% so far) than he did last year. I have no opinion on his usage, and I think it has more to do with the counts he's found himself in than with any purposeful change.
9. Explanation two: Starting spot on the rubber. Early on in the season, Yossi noticed that Rodney had moved back toward the middle of the rubber. It was a good catch, but it's not the culprit. Take a look at Rodney's release point on Brooks Baseball. He's back on his 2012 spot now (although with some wider variance).
10. Explanation three: Tipping pitches. This, from R.J. Anderson, is interesting, but I don't think it's the problem. The problem isn't that Rodney is getting hit, it's that he isn't throwing strikes.
11. Explanation four: Toe tap. Once again, Jason Collette is on the spot with what I think is the best explanation. Rodney's mechanics have changed (pay wall). He's incorporating a toe tap, and he's tilting his body more than he used to. For extreme shifts in control, I'm most comfortable believing in mechanical problems.
12. Explanation five: World Baseball Classic hangover. This is difficult to prove, especially since Rodney pitched well in the WBC, but it's also difficult to disprove. It just sort of sits there like an old piece of flypaper, attracting some flies but not trapping them, and not attracting others.
13. Explanation six: He's lonely. This is my personal opinion. It's not analysis, but in a weird situation like Rodney's, oh well. I believe that with Carlos Pena gone, Fernando has no friend to watch his imaginary arrow with, and that makes him sad. Loney should get on this immediately (could it hurt?). If this is the case, then we haven't been giving Pena enough credit. Sure, he was barely above replacement level in 2012, but if you award him Rodney's 2.3 fWAR, his signing looks a lot better.