Exploring Fernando Rodriguez's Struggles

Despite having around a 4 earned run average (ERA) last season, Fernando Rodriguez was one of the better options coming out of the bullpen. In 52 innings, he had 14 shutdowns to 9 meltdowns; not great but solid.

His FIP and xFIP were a little bit higher than his ERA which mean he got a little bit lucky; further confirmed by his 79.4% left on base percentage (LOB%), average is around 70-75%. He struck out 9.8 batters per nine innings (K/9) and walked 5.16 batters per nine innings (BB/9). The walks are a little disheartening but Rodriguez is young and typically had numbers in four's and three's in the minors.

Finally, Rodriguez's batting average on balls in play was a little high at .333 which would lead one to assume that he was due some regression in his favor. That's happened but it hasn't worked in his favor.

This season Rodriguez is pitching almost as well as he did last year, but with drastically different results. This is why you'll hear us call relievers volatile, they epitomize the small sample size phrase.

Rodriguez 4.69 FIP and 4.84 xFIP is only a little bit higher than his 2011 numbers and well below his current 6.17 ERA. His LOB% has gone the entire other way and at 60.4% is well below average for the statistic. His .292 BABIP, however, is actually better this year than it was last year.

His 9.51 K/9 and 5.66 BB/9 is only slightly worse than his 2011 numbers, but maybe that's enough.

Let's go a little further down the rabbit hole.

Lets look at his Pitch F/X values cpurtsey of FanGraphs. Rodriguez's uses primarily a four-seam fastball and a curveball. In 2011 his curveball was the better pitch, but this year it's been his fastball that's the better pitch.

In 2011 his wFA was -.2, this year it's 5.2. In 2011 his wCU was 2.3, this year it's -2.7.

What's interesting is that his splits between the two pitches aren't that much different from 2011. Meaning he's throwing his fastball and curveball just as much as he was last year.

Using Brooks Baseball's PitchIQ score we see a slight improvement in Rodriguez's Whiff/Swing with the four-seam fastball and similar results from 2011 to 2012 with his curveball Whiff/Swing.

Using Texas Leaguers we can confirm that slight improvement in whiffs, however if we look at the In Play percentages we start to get a clearer picture of what's going on with Rodriguez. In 2011 Rodriguez's curveball had an in play percentage of 10.7%, this year it's been 14.6%. Which goes a long with the difference in pitch values on FanGraphs.

Digging into the Texas Leaguer graphs two things stand out to me: his release point and the spin movement on his curveball.

2011 Release Point - closer to 3/4 slot, but more specifically it's between -1 and -2 to the left of the catchers perspective.

2012 Release Point - This is closer to over the top and between -1.5 and -.5 to the left of the catcher's perspective.

Is that change in release point enough to make Rodriguez more hittable? Maybe.

Let us look at the Spin Movement data.

2011 Spin Movement - The vertical movement of the curveball is clumped near -10.

2012 Spin Movement - The vertical movement of the curveball is clumped near -5.

It's hard to see but if you start at it long enough you'll see a slight difference.

Is there enough of a difference in Rodriguez release point and curveball movement to explain his struggles? Maybe, I'm far from an expert when looking at these graphs, but it's the only explanation I can come up with. Overall his Pitch F/X data outcomes and peripherals would suggest that he's not pitching all that bad, even his velocity on both pitches has increased, yet teams are finding him very hittable at the moment. Maybe it's something mechanically, maybe it's something he's broadcasting to the hitter or maybe it's a small sample size issue. I'm not entirely sure, but from what I've gathered it's something with his curveball and how he's using it.