Eduardo Rodriguez needs his full arsenal

I know I’ve said it before, but I’m getting myself excited about the Red Sox rotation in 2017. The unit was a legitimate strength in the second half of this past season, and all of those pieces should theoretically be back after the offseason. Sure, we could see some regression from Rick Porcello, who is coming off the best year of his career. On the flip side, we should see that counter-balanced by a better year from David Price, who was as bad and inconsistent as he’s ever been.

Beyond those two, they are hoping from a full season from Drew Pomeranz, who showed real promise both in San Diego and after coming over to Boston. Even Clay Buchholz and/or Steven Wright have much higher upsides than we typically see from a fifth starter. Then, there’s Eduardo Rodriguez, who could be the real difference between a good rotation and a great one.

For the young lefty, 2016 was a tale of two halves, as Ben noted in September. As he said, the overall numbers this year do not indicate a strong pitcher capable of being a big part of a great rotation. He finished the season with an ugly 4.71 ERA and even uglier peripherals. Specifically, Rodriguez pitched to a 4.31 FIP, a 5.11 DRA and a 115 cFIP. Nothing about that is encouraging.

However, if you only look at his second-half numbers (which also coincide with him being recalled after a stint in Triple-A), we see a much different pitcher. He made 14 starts in that stretch, tossing 77 innings in that span. At the end of that stretch, he had pitched to a 3.24 ERA while striking out 79 batters (25 percent), walking 28 (9 percent) and allowing a .613 OPS. Even if that’s not an ace, those are the numbers of an arm who can be legitimately counted on in October.

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Oftentimes, we take second-half numbers too seriously. While those numbers are certainly encouraging, it’s too easy to just erase Rodriguez’s first-half numbers. Those massive struggles still happened, and it’s entirely possible we’ll see that version of him again in the future. What we really want to look for are tangible reasons to expect the change in numbers to carry over to a full season. Luckily for Red Sox fans and Rodriguez, there is one big piece of empirical evidence that should help the southpaw be more consistent in the future.

If you’ve been following his career closely since reaching the majors, you can probably guess what that change is. One of the biggest criticisms of Rodriguez over his entire career is that he hasn’t been able to consistently utilize his full repertoire at all times. He should be a three-pitch guy, which is enough to keep hitters off balance and produce strong starts most of the time. However, he too often resorts to just two pitches, sometimes abandoning his changeup but usually tossing aside the slider.

Looking back at his pre-July stints, he relied heavily on his fastball, throwing his hard stuff (fastball, sinker, cutter) about three-quarters of the time, and his changeup another 20 percent of the time. These pitches can both be effective at times, but as we saw from the results over this span of the season, it’s not a strategy that works for starters. If Rodriguez is pitching like this on a consistent basis, he might as well be throwing from the bullpen.

In the post-July 1 run, however, things changed dramatically. The hard pitch frequency was reduced to about 65 percent of the time, and his changeup usage was downgraded to a shade under 15 percent. This left enough room for him to utilize his slider almost 19 percent of the time. While still a pitcher who relies heavily on his fastball, this is more of a mix that will work in the rotation, and it’s the biggest reason we saw such a big improvement from Rodriguez.

The correlations continue when you look at his best starts of the season. Judging by Game Score (probably not the best measure, but certainly the easiest), I looked at Rodriguez’s five most effective starts of 2016. Unsurprisingly, all five of them came in the second half. In fact, you’d have to go to his ninth best start before finding one in the first half. Looking at those top-five outings, here are the slider usage-rates from each outing: 13 percent, 20 percent, 10 percent, 31 percent, 9 percent. Obviously there is a pretty wide range here, but all of those rates are higher than his first-half averages, and a couple of them are higher even than his second-half average.

The moral of the story is he needs to work this pitch in on a consistent basis if he’s going to have success as a starter. It’s a strong pitch, as it induced whiffs on about 30 percent of swings over the full season, while also inducing a ton of pop ups, which are essentially as valuable as strikeouts. One can see why he’s somewhat apprehensive towards throwing it, as he has a tendency to hang one every once in a while and allow home runs on the pitch. Over the second half, none of his offerings allowed more home runs per fly ball. Still, that’s a risk Rodriguez has to be willing to take and he won’t be able to get over that issue unless he pitches through it.

The Red Sox should have a good rotation in 2017, and Rodriguez should be a big part of it. Wherever you want to pencil him into the rotation, he has the ability to be above-average in the slot (assuming the top two spots are occupied). If he wants to consistently succeed, though, he needs to use his full three-pitch arsenal rather than relying on two pitches a night. As long as Rodriguez is willing to lean more on his slider, despite some home run issues, he should be ready to take a step forward in his age-24 season.