In the Roberto Hernandez versus Jeff Niemann debate, I sided with Jeff Niemann. When healthy, Niemann provides strong but limited innings. Roberto Hernandez is known for doing the opposite, pitching many innings but allowing high run totals. With Niemann's diminished velocity and his injury relegating him to the bullpen and then the DL, Roberto Hernandez has the fifth spot all to himself (at least until Archer forces his way to the majors).
In my season preview of Roberto Hernandez, I identified several possible adjustments Hernandez could make to find success in the bullpen. While he is instead a member of the rotation, the adjustments I advocated for still hold merit in a starting role.
My first suggestion was for him to cut back or eliminate his four season fastball usage.
Throughout his career, Hernandez has really struggled with his fastball. In the six years of recorded data by Brooks Baseball, hitters have teed off on his fastball, hitting .379 with a .663 slugging and a .393 TAv. He generates whiffs on only 9.70% of his fastballs, a rate below that of his other three pitches. And while his three other pitches also produce ground balls, his fastball's ground ball percentage per balls in play is only 38.33%. Even when he was throwing much harder in 2007, he still struggled to use the pitch successfully. The pitch is not exclusive to a specific handed batter either, although he throws it a little more often against left handed hitters.
Since the pitch does him few favors and is not thrown much harder than the sinker, it makes sense for the Rays to encourage him to drop the pitch.
In his first start of the 2013 season, Hernandez threw his four-seam fastball only five times. For a pitch that he used to throw about one out of every five pitches, the decline is steep. During yesterday's start, Hernandez threw his four-seamer a total of three times. It is only two starts, but it looks like this is a real, intentional adjustment by Hernandez, and is definitely something to monitor for the rest of the season.
I also proposed that Hernandez should hurl his two off-speed pitches (change up and slider) more frequently.
To occupy that vacancy, he should, in my opinion, ramp up the usage of his slider and change up to the point where he is throwing them (combined) close to 40% of the time. If he throws the sinker 60% of the time, the change up 25% of the time, and the slider 15% of the time all while registering the same results, his TAv, in theory, should be about .247. As shown by that exercise, by simply losing the four seam fastball (career TAv of .393), he should immediately become a better pitcher.
As is the case with most right handed pitchers, the change-up is a vital off-speed pitch in neutralizing left handed hitters. Owning a career 30.24% whiff per swing rate, a .209 TAv against, and a 65.12% GB/BIP%, his change-up is a true plus pitch. His slider, while not of the same quality as his change-up, still produces respectable marks. Against the pitch, batters whiff on about 25% of their swings, have a GB/BIP% of 45.42%, and hit for a .237 TAv.
Sure enough, in his first start, Robert Hernandez mixed in his change-up 28% of the time and his slider 15% of the time, figures very close to my suggested target of 25% and 15%. His second start yesterday was very similar, with 30% of his pitches change-ups and 14% sliders. These ratios rest far above his career change-up and slider frequency percentages, which sit at 16% and 12% respectively.
At this point, it is far too early to judge the results and deem whether or not these changes are beneficial. While his first two starts have been unremarkable at best, they both require context. In his first start, the red-hot Chris Davis inflicted most of the damage. Last night, the BABIP luck dragons got the best of him.
In theory, these tweaks to his arsenal should generate healthier results; however, only time will tell if the positive results come to fruition. Regardless, it is definitely a storyline worth following.