Francisco Rodriguez hasn't been pitching well since early August

On the surface, Francisco Rodriguez has been a godsend for the Tigers this season. He has 44 saves, which is the second-most by a Tiger since 2000 (and it comes with 75 percent less stress than 2011 Jose Valverde!). After suffering through the Valverde train wreck in 2013, the Joe Nathan Experience in 2014, and whatever Joakim Soria and Bruce Rondon combined for last year, there can be no underestimating what Rodriguez has done to save Tigers fans’ collective blood pressure in 2016.

Yet, not everything is right in the world of K-Rod. His five-run meltdown against the Kansas City Royals on Saturday was the culmination of a long, ominous trend that bode ill for Rodriguez in the long-term. In particular, things have not been right with Rodriguez since the start of August.

He has only struck out 11 batters in his last 19 appearances, a very paltry rate of 5.30 per nine innings. Couple that with a walk rate of 3.86 per nine innings and a home run rate of 0.96 per nine innings, and presto! The 2014 version of Joe Nathan has been reincarnated.

It may just be that K-Rod’s strikeout rate is just in a rut. After all, he has managed to get a swinging strike rate of 11.5 percent over those same 19 games, which, while not amazing, is nothing to sneeze at. However, it is possible to get a decent amount of whiffs without having a true put-away pitch, and right now it looks for the world like K-Rod does not trust his changeup like he did earlier in the year.

Take a look at his pitch usage chart for the season.

Rodriguez is fading his changeup — his best pitch, per FanGraphs’ pitch values — in favor of his worst pitch, the fastball. It’s a bold strategy that I would estimate has something to do with familiarity. One does not get to be as successful as Rodriguez has been for as long as he has been without being a very smart pitcher.

My best guess is that Rodriguez is mixing his pitch usage more to counter the fact that American League hitters have now seen him for a full year. In theory, this strategy has merit. But how has it worked?

Not well. Not well at all. If anything, this plot is more mystifying than anything else, because Rodriguez is having even more success with the changeup than ever before. So, why is he not using it? Maybe it’s a feel thing. Maybe it’s just a sample thing, and he faced several hitters that James McCann wanted to attack with the fastball, and we won’t see this anymore.

Ultimately, Rodriguez is faced with a situation that requires him to make one of his famous adjustments. Over the last two months, he has been losing all three of the true outcomes: too many home runs and walks, and not enough strikeouts.

His ground ball rate is high enough that he can get away with being a glorified Mike Pelfrey-type pitcher, but that will require him to take firm control of at least one of those true outcomes. This adjustment had better come quick if K-Rod hopes to buck the trend of Tigers’ bullpens causing heartburn in October.