What's wrong with Joe Nathan?

By now we are probably all familiar with Joe Nathan's story. He spent the better part of a decade torturing Tigers while a member of the Minnesota Twins, establishing himself as one of the most dominant closers in the game. At age 37 he finally, mercifully, left the AL Central to pitch for the Texas Rangers. In his two years in the Arlington heat he refused to allow his age to show through, posting a 2.09 ERA while recording 80 saves in 86 opportunities.

And that brings us to 2014. Last off season, Dave Dombrowski signed Nathan to a two-year contract worth $20M, with a team option for a third year at an additional $10M. At age 39, some saw this as a risky acquisition, but Nathan's performance provided little cause for concern. The only red flag was the four-digit number next to his birthday.

Early in the season, Nathan struggled to get outs. In his first four appearances, from March 31 to April 9, Nathan allowed five runs on six hits and four walks. He blamed the performances on an affliction referred to as "dead arm," and stated that this was a common occurrence for him. The numbers backed that up, Nathan has historically been a slow starter.

After that, Nathan went on a tear in which he looked exactly like he always had. 13 appearances, 13 innings, 13 strikeouts, and 10 saves in as many chances. His 0.69 ERA over this stretch had nearly erased the damage done in his first four games.

Then everything fell apart in an instant. Since that torrid streak, Nathan has come into nine games and was only able to get out of an inning without giving up a run in three of them. Since May 17th, Nathan has posted a 15.43 ERA and blown two of his four save opportunities. He also picked up a loss after giving up four runs to Toronto in the ninth inning of a tie game.

Simply put, he has been awful. So what's the problem?

Depending on whether you believe the PitchF/X data from Fangraphs or Brooks Baseball, his velocity may or may not be down this year. The movement on his curveball has decreased, but overall there isn't any glaring issue in the data that you could blame for pitching this poorly.

Ultimately, it looks like his issues are less with his "stuff" and more with the fact that he has lost all semblance of control.

It could be that his age has finally caught up with him, but that wouldn't explain why he was as dominant as ever for over a month earlier this season.

Could he be dealing with an injury, or did he simply lose something in his mechanics? Is this just an extreme example of baseball being a strange, cruel, mysterious game?

What do you think?