Detroit Tigers Bullpen Has Best FIP in American League


It’s easy to get one week, two weeks, or even a month into a season and be overly concerned about the performance of one particular position or player. This is especially the case when the position in question was supposed to be a trouble spot for the team from the get-go.

April 7, 2013; Detroit, MI, USA; Detroit Tigers relief pitcher Phil Coke (40) pitches in the eighth inning against the New York Yankees at Comerica Park. Mandatory Credit: Rick Osentoski-USA TODAY Sports

The bullpen appears to be one such area of concern for the Detroit Tigers. They were unable to name a closer when spring camp broke, and they’ve struggled their way through the first six games of the season. As a group, they’ve been charged with 14 earned runs (plus whatever number of inherited runners) in 19.2 innings. That’s a 6.41 ERA – third worst in the American League.

But the situation may not actually be quite as dire as is seems. Some things have gone poorly – all the hits and walks, mostly – but they’ve yet to allow a home run, and they’ve collectively struck out one-fourth of the hitters they’ve faced (just more than, actually), so there are some very good things going on as well. Perhaps a bigger issue than all of the walks they’ve issued (over five per nine innings) and the elevated BABIP (.340) is that they’re not doing well in keeping runners on base.

Relief pitchers last season left 74% of runners on base (with every team finishing plus or minus 7%). The Tigers this season have left only 54%. That 20%-ish is actually a big deal. Detroit relievers have allowed 31 base runners, so 20% equates to just over six extra runs. Thos six extra runs – in 19.2 innings – has inflated the bullpen ERA by 2.80. There’s some debate about how much control a pitcher has over sequencing and strand rate, but a large chunk of that can be chalked up to plain bad luck.

According to FIP – an ERA estimator/approximator of sorts – the Tigers bullpen has actually been very good. FIP doesn’t take an opinion on sequencing or balls in play, instead using only home runs allowed, walks allowed, and strikeouts into consideration (recent iterations also include infield pop-ups). These are thought to be the aspects of pitching that a pitcher has the most direct control over.

Tigers relievers have combined for a 2.64 FIP – fifth best in all of baseball and best in the American League. What that says is, given the number of strikeouts, walks, and home runs, the Tigers’ bullpen would be expected to have an ERA much closer to 2.64 than the actual 6.41. We can expect the Tigers to get better production out of their bullpen without having to shake things up just on expecting their luck to change.

It’s too easy (and probably improper) to simply dismiss everything as luck early on in the season when the sample sizes are small, but that’s really all we have to go on right now. FIP is surely an oversimplification of pitching – just like AVG, OBP, SLG, and OPS are each oversimplifications of hitting – but it’s a good measuring stick to place next to ERA.

Jim Leyland and the Tigers do need to figure out how the bullpen pieces are going to fall into place, and they need to do a better job of putting players in position to succeed (like limiting opportunities against right handed hitters for Phil Coke), but the struggles to-date aren’t the complete fault of the manager or the players. Sometimes pitchers get poor results, and it doesn’t always mean they were put in a bad spot or that they even were pitching all that poorly.