Why is Eduardo Núñez getting so much playing time?

The Boston Red Sox have a strong analytics department, as well as baseball minds that far surpass my own. Perhaps they have a strong rationale behind starting Eduardo Núñez in the postseason as often as they have, because doing so for the platoon advantage is not a reason I find to be convincing, and that has not always been the case either.

Núñez was one of the worst players in baseball during the 2018 season. He hit only .265/.289/.388 with a minuscule 3.2 percent walk rate. His 78 wRC+ ranks seventh-worst among hitters with at least 500 plate appearances. One might think that such a batting line is not too terrible for a utility infielder, as they tend to be good defenders. In the case of Núñez, that would be incorrect. He is a poor second baseman and does not really have the arm for third base, though given the option, third base is where I would rather have him play. To make matters worse, the speedy infielder was also one of the worst baserunners in the league. A good chunk of that were the 17 double plays he grounded into, but he also ran the bases poorly when he was not trying to steal. He was a sub-replacement level player at both FanGraphs and Baseball Reference.

Craig Kimbrel might be a problem

Photo by Mike Stobe/Getty Images

When your relief ace can’t throw strikes, that’s bad.

There is some semblance of reason to starting Núñez against left-handed pitchers, but why start him against Masahiro Tanaka and Justin Verlander? I understand that the left-handed hitting Brock Holt and Rafael Devers are not very good at third base either — Devers badly misplayed a ball off of Alex Bregman in Game 3 that led to a run scoring — but they are not so bad that the Red Sox should forsake the platoon advantage.

Speaking of the platoon advantage, it is not some catch-all that covers all hitters. In other words, for example, the worst right-handed hitter is not better versus left-handed pitchers than the best left-handed hitter. It seems that managers and front offices generally understand that, but the Red Sox might want to take a closer look with the their third base situation.

About six months ago I wrote an article about the Red Sox’s struggles against left-handed pitching. In that article I regressed some players’ platoon splits to determine their true talent versus left-handed pitchers. Believe it or not, I found that Holt had a better projected wOBA against lefties than Núñez did, despite lacking the platoon advantage. If I were to rerun those numbers, that gap would be even larger with how poorly Núñez has hit this year.

Devers had an even better projected wOBA against lefties than Holt! I understand that he had a disappointing season at the plate, but he is only 21 years old with plenty of time to become the hitter scouts expect him to be. Even as is I would rather have him face a left-handed pitcher instead of Núñez.

Thankfully I have not seen nor heard anyone point out Núñez’s career reverse splits as a viable reason to start him against right-handed pitchers. As shown by research done in The Book, no hitter has true-talent reverse splits. In the article I linked to above, I found that Núñez’s true-talent splits have him as slightly better against lefties.

Núñez was actually doing well in Game 3 before getting pulled for reasons that were not clear at the time of this writing. He was 1-2 and made a nice snag on a difficult play at third. Before that though, he was hitting .143/.250/.214 in 16 PA. Amazingly that includes two walks.

This is probably a stretch, but I would not argue against playing Blake Swihart at third base over Núñez. Yes, I know he has only played 11 inning there this year. That being said, he is very athletic and obviously has a great arm. His numbers for the season are even worse than Núñez’s, but he has been an average hitter since the beginning of July. He is a switch-hitter and was a highly touted prospect for a reason. I think there is still upside in his bat, but I understand not wanting to risk it in the postseason.

The Red Sox’s insistence on continuing to play Núñez is puzzling. Holt and Devers are probably better options regardless of pitcher handedness. The Sox are up 2-1 in the series and might win regardless, but against this Astros team every little bit helps.