How John Farrell Manages the Red Sox Bullpen

This is my 13th article at Check Down. It is also my first pertaining exclusively to the Red Sox. As a diehard Sox fan, I’m a bit surprised that it took this long. Perhaps it’s because I’m superstitious, and don’t want to “mess” with any of the success they’ve been having– because my writing definitely affects their on-field performance, right?

In any case, this article will be about the role of the Red Sox manager, John Farrell. More specifically, it will analyze Farrell’s bullpen use– is he using the right relievers in the right situations?

One of the hardest things to do in the game, in my opinion, is to quantify the ability of the manager. There’s so much data and statistics out there that help us track the performance of players, but other than looking at a teams’ win total and a fan’s subjective opinion of a manager’s choice of reliever or pinch hitter, there are few ways to measure the performance of the manager.

What makes it difficult is that the manager plays so many different roles on a team. He is a manager of people– trying to keep team morale up despite dealing with 25 guys with 25 different personalities playing together for 162 games in 180 days. He is an in-game tactician– creating the lineup, choosing when to substitute players, positioning fielders, calling for steals and sacrifice bunts, and more. He is also the liaison between the front office and the team. A lot of times the front office has suggestions for the aforementioned decisions and it is up to the manger to employ them. Sometimes this relationship is healthy, and other times, not so much.

Before I get into Farrell’s use of the Red Sox bullpen, I want to outline some of the metrics I’m using:

Win Probability Added (WPA): measures how each in-game event impacts the likelihood of winning. For example, say the Red Sox have a 50% chance of winning a tie game in the bottom of the 9th inning when David Ortiz hits a walk-off home run. The win expectancy jumps to 100%, so the WPA on the play is 0.50 and is credited to Ortiz. Correspondingly, the opposing pitcher would be given a WPA of -0.50.

Leverage Index (gmLI): the average leverage index when a pitcher enters the game. Leverage index quantifies the amount of pressure in a game event. A pitcher who enters the game with the bases loaded faces much more pressure than a pitcher who enters with no one on base. An LI of 1 is average. Anything over 2 is considered high leverage and anything under 0.85 is considered low leverage.

WPA/LI: This shows a player’s WPA while controlling for LI. Not every pitcher will have the same LI– some enter the game in high-pressure situations (closers) while some enter the game in much lower pressure situations (mop-up guys). A pitcher may have a higher WPA simply because he enters a game with a more volatile win expectancy. WPA/LI allows us to compare players.

So take a look at this chart with the Red Sox seven most used relievers, sorted by innings.

Screen Shot 2016-07-18 at 9.47.20 PM

Some things to note:

  • Kimbrel has been used the in most pressure-filled situations. This makes sense– he’s the closer. However, he’s actually decreased the Red Sox chances of winning over the course of the season (WPA of -0.10). This is most likely a result of a few really bad outings. Kimbrel has given up runs in 6 outings this season. In 5 of those he’s given up more than 1 run. While he’s the worst Sox reliever at generating wins (WPA/LI of 0.20), I’d say it has more do to with a few bad outings in a small sample size than his true talent level. He’s good, he will be fine.
  • Tazawa and Uehara enter in the second most pressured situations. They’re usually the 7th and 8th innings guys and often come in with inherited runners on base. They’ve done fairly well, both have positive WPA, but rank towards to lower end when comparing the staff has a whole. Their WPA/LI is around 0.20.
  • Barnes, Ross, and Hembree have pitched well in low-pressure situations. And when comparing them to the high-pressure guys, they’ve actually performed better. Their WPA/LI is in the 0.50-0.60 range. Maybe it’s time to give them seem more high-pressure innings.
  • Layne has also pitched well in low-pressure situations, but I’d be a little more hesitant to given him high-pressure innings. He doesn’t quite have the same stuff that those three guys do.

In general, the Red Sox bullpen has pitched well– which makes it hard to critique Farrell’s decision-making. Any option he chooses can really be justified. But with Tazawa and Kimbrel now on the DL (albeit with the Ziegler addition), some of the guys who have pitched well in low-pressure situations will be given a chance to prove their worth in high-pressure innings. Farrell will have to get more creative with two out of his three most high-pressure relievers not available. It will be interesting to see how it plays out, so long as he’s there to see it.

Posted by Jeb

From the great "vacationland" state of Maine. Former D3 baseball player on an underachieving team. Prior: TrackMan with A's. Current: Check Down Sports. Soon: Video with Reds. All-time facial hair lover.

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