Tampa Bay Rays: Why Brad Boxberger Has Fallen Off Part 2

A week ago here at Rays Colored Glasses, we discussed how altered pitch usage has played a role in the decline of Tampa Bay Rays closer Brad Boxberger this season. If you have some time, I would recommend giving that piece a read (or reread) before you get into this one, but here’s the quick version: Boxberger is throwing many fewer pitches in and (separately) pitches up to righties compared to his breakout 2014 despite the success he had that season. It is also quite amusing that he is throwing down more to righties considering that he is actually doing the opposite to lefties. The next questions we need to answer, though, are why the Rays made those shifts and what their effects have been.

We went with the graphs from Brooks Baseball last time, but while we are still going to be using Brooks Baseball data, the graphs aren’t really necessary for this piece. In any event, let’s get right into our analysis for today, which will be how Boxberger’s fastball has done against right-handed pitching based on the horizontal divisions of the strike zone. The statistics we will use are slugging percentage–mostly because it encompasses batting average and because extra-base hits are worse than singles–and whiff rate, which is a good measure of the dominance of pitches, especially for a strikeout pitcher like Boxberger.

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The disclaimer with those numbers is how often Boxberger has gone inside and outside, which is what we talked about in the last piece. So you don’t need to look back and forth, here is a quick shorthand: Boxberger threw 1.27 pitches outside to right-handed batters for each pitch inside in 2014 before bumping that up to 1.94 pitches outside for each one inside in 2015.

If you look at the slugging percentage in 2014, it seems pretty clear why Boxberger has been going away more often this season. Righty batters couldn’t do anything on fastballs away against him, managing just a .071 SLG compared to .276 on offerings inside. Going inside less should also make such pitches more effective when he does go to them, and that has turned out to be true in terms of both slugging percentage and whiff rate. However, the rest of the numbers explain why that strategy has not been successful.

Firstly, we just talked about how Boxberger’s fastballs inside would be more effective if he threw them less, and the logic follows that Boxberger’s fastballs away wouldn’t be as good if they became a bigger part of his arsenal. The question was going to be how much worse they became with more use, and the answer has been a good deal worse. His slugging percentage on pitches away jumped to .222–but that is still pretty good. The bigger issue is his whiff rate, which slid from 15.8% all the way down to 6.3%. Boxberger isn’t missing any bats with his heaters away as the ones in the zone have been fouled off while the ones outside of it have been taken for balls. That has led to more pitches out of the zone for walks and made him more dependent on his changeup for whiffs.

Next we can talk about how throwing inside less has affected Boxberger’s pitches down the middle. We know the way that the saying goes–if you throw inside, it makes hitters less comfortable in the batter’s box. It puts something in the backs of their minds and they aren’t as comfortable leaning out over the plate. There is a correlation does not imply causation issue with the fact that Boxberger has allowed a higher SLG and forced a lower whiff rate on pitches down the middle this season, but the whole “strength of pitching inside” is at least worth mentioning.

That leads us to our final and perhaps most compelling reason: Boxberger’s fastball usage lines up extremely poorly with the locations where he likes to throw his changeup. In 2014, Boxberger threw 2.16 changeups inside  to right-handed batters for every one away, and in 2015, he has reduced that only slightly to 2.06 inside for each one outside. Boxberger is more comfortable throwing his changeup inside to righties, but now those pitches are less effective. We can see now that his fastballs inside were not just to keep hitters uncomfortable–they were also to set up his changeup.

Boxberger sells his changeup well, throwing it from the same arm slot as his fastball and with the same exact arm speed. However, he Rays had him voluntary give up a third layer of deception–the fact that it comes towards the same spot that he just threw his fastball. If Boxberger gets ahead in the count 0-2 with two fastballs on the outside corner before suddenly coming in, the hitter would have a better idea that the offering was a changeup even if he couldn’t recognize it at all out of Boxberger’s hand.

Here’s something funny–Boxberger’s whiff rate on pitches inside has actually gone up from 15.0% in 2014 to 17.6% in 2015. It has been such a good pitch that it has missed bats even without that third layer of deception. However, he has allowed harder contact when such pitches have been put into play, and hitters have done a better job swinging at it only when it has gone for strikes. Add in the fact that Boxberger can’t throw his changeup away to righties–he literally hasn’t forced a single whiff on an outside changeup to a righty batter this season–and Boxberger’s change has been less effective right when he has needed it most.

Now we can go back and combine the last few things that we have said. Boxberger’s increased usage of fastballs away has helped him force weaker contact but also reduced his ability to generate whiffs with his heater. That has made him more dependent on his changeup for strikeouts. However, his changeup is actually worse now because it worked much better with his fastball in and he has issues throwing it down and away. Overall, Boxberger has given up weaker contact versus righties–his ISO against has gone down from .191 to .159–but only at the cost of fewer strikeouts and additional walks. There is no way to call that a net gain.

We will stop here for today, but if there is interesting in continuing, we can talk about Brad Boxberger’s tendencies in the vertical strike zone against right-handed batters next time. There are still many things to wonder about why the Tampa Bay Rays changed Boxberger’s pitch usage.

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