After a solid rookie campaign, Eduardo Rodriguez struggled mightily in the first half of 2016. The second-year starter has bounced back with two solid outings, but is he for real? Ian York uses PITCHf/x to attempt to determine if the talented lefty has put his struggles behind him.
Eduardo Rodriguez was one of the few bright spots for the Red Sox in 2015. His major-league debut on May 28 was supposed to be a spot start, but allowing just 3 hits over 7 ⅔ innings suggested that he was a better option than the alternatives. He ended up with a very impressive rookie season: 21 starts with a 10-6 W-L record and a 3.85 ERA (110 ERA+).
His 2016 season has been much less impressive. Injured in spring training, he was underwhelming to downright bad in his return to the majors, with an 8.59 ERA in his first six games. After a horrific start on June 27 against Tampa Bay (2 ⅔ innings, 11 hits, 9 runs) he was sent back to the minors, and didn’t return until July 22. His two games since his return, however, have had much better results: 12 ⅓ innings pitched with a 2.19 ERA. Are there any signs that these two games represent a true turnaround?
Rodriguez in 2015 threw three (or perhaps four) pitch types: Four-seam fastball (“FF”), slider (“SL”), and changeup (“CH”). PITCHf/x also identifies a two-seam fastball or sinker (“FT” or “SI”), but in practice his fastballs form a single cluster of pitches in terms of movement and velocity. In the charts here, I have recategorized his pitches and called all his fastballs “FF.”
Not many major-league starters have long-term success with just three pitches, and in 2016, Rodriguez added a fourth pitch, a cutter (“FC”), faster than his sliders but with much more movement than his fastballs – the gold dots in this chart:
However, he only used the cutter in three of his first four games this season, and seems to have abandoned it since then. In his last two games, he greatly increased the use of his slider and concurrently reduced his changeup usage:
His fastballs in 2016 have good velocity, though they are somewhat slower than in 2015. He started off relatively slow and gradually increased speed through his first five games back, dropping off slightly since then and remaining about 1 mph slower than his average from 2015 (about 93.5 vs last year’s average of 94.5 mph).
Much has been made of Rodriguez tipping his pitches. In 2015, it seemed to be an intermittently serious issue – especially for his slider – and many have made the assumption that Rodriguez’s struggles in 2016 are for the same reason. However, while there may be some contribution from pitch-tipping, it is hard to make the case that it’s the sole reason for his ineffectiveness since each of his pitches in turn have had problems.
To compare pitch effectiveness, I looked at total bases per 100 pitches (as well as balls per 100 pitches, but Rodriguez is generally about league-average for balls, so I won’t show it here).
|Total bases per 100 pitches|
|All pitchers, 2016||Rodriguez, 2015||Rodriguez, 2016|
Both in 2015 and 2016, his fastball is close to league average – a little better in 2015, a little worse in 2016. His slider in 2015 was just bad, far worse than league average, perhaps because of his tipping issues; in 2016, his slider has been better, close to league average. However, his changeup has been much worse, going from above average in 2015 to a terrible pitch in 2016. By comparison, the cutter that he has been experimenting with has been extremely effective, far better than league average.
(It’s important to point out here that this approach doesn’t measure the full value of a pitch. A changeup may be ineffective on its own, but might more than compensate for that by adding deception and increasing the value of other pitches.)
Now we can compare pitch value per game in 2016. Keep in mind that the sample sizes are now very small, so this needs to be taken with a grain of salt:
|Total bases per 100 pitches|
|May 31||June 5||June 11||June 16||June 22||June 27||July 16||July 22|
His change was terrible on June 5 and 11 (and July 16, but he only threw five changeups that day); his fastball was bad on June 16 and 27; his slider was awful on June 22 and 27. This doesn’t seem like a problem with tipping a specific pitch, it seems like a general issue with poor quality pitches.
Last year Rodriguez showed that he can perform at the major-league level, and his latest two games offer some hope that he can return to his 2015 level. However, he improved his performance mainly by almost dropping his least effective pitch type, the changeup, without replacing it with another pitch. It is hard enough for a starter to succeed with just three pitches, and it seems unlikely that Rodriguez will be able to continue as a starter as just a fastball/slider pitcher. He has shown what seems to be a very effective pitch with his cutter, but even if he does begin to incorporate that into his mix, he will certainly need to improve his changeup quality before he can reliably be a high-quality starter in the major leagues.