Francisco Rodriguez is throwing his pitches slower, in worse locations, and with worse results. Below is some data on Rodriguez’s performance, courtesy of Brooks Baseball. Keep in mind that sample sizes for 2016 are small.
The above charts show an overall decline in velocity for all four pitches. Most significantly, Rodriguez’s fastball has lost about two miles per hour since he consistently sat around 90 mph last year.
Grooved pitches are those thrown in the middle-middle of the plate, regardless of movement or velocity. According to PITCHf/x data from Baseball Savant, pitches thrown in this center part of the strike zone (Zone 5) result in a home run, triple, double, or lineout 8.33 percent of the time. Pitches in all other zones derived similar results 3.34 percent of the time. (Numbers are based on results of American League pitchers in 2015 regular season).
It’s worth noting that Rodriguez’s numbers for 2016 look less significant when you split the statistics into smaller samples. One can see then that he has experienced some similar lows in his career. But still, the data are worrying. Everything seems to be trending in the wrong direction.