Does Bullpen Success Lead to Outperforming Expectations?
In a recent ESPN article, Jayson Stark wrote about the Kansas City Royals and how they continually outperform their preseason expectations.
He listed several factors as part of the equation to their success, one of which included their superior bullpen.
In it, Stark interviews Sam Miller of Baseball Prospectus, who wrote an article pondering this very issue back in February.
Miller had this to say: "The team with the best bullpen is virtually always going to outperform its projections, but that team with the best bullpen is extremely hard to identify in advance."
This idea about superior bullpens helping lead to greater success than expected got me thinking. Do teams with the best bullpens really surpass their preseason expectations?
If we look at the top-10 bullpens ranked by FanGraphs' Wins Above Replacement (fWAR) at the end of last season and then compare their projected record (via FanGraphs) and their actual record, we get the table below.
|Team||ERA||xFIP||fWAR||Proj. Record||Actual Record||Difference||Playoffs|
I included the Kansas City Royals in the table because they won the World Series. Their bullpen fWAR ranked 15th-best last season.
This table shows us that seven of these teams surpassed their projected win total (eight if we include the Royals), and all seven also made the playoffs. Breaking it down further, 8 of these teams won at least 72 percent of the time in 2015 when leading after the 6th inning, and the same can be said for leading after the 7th inning (via SportsDatabase.com).
The World Series champion Royals won 85 percent of the time in 2015 when leading after the 6th and 7th inning.
There are more factors at play here as to each team's success -- or failure through significant injuries in the case of the Washington Nationals -- but at first glance, it appears as though Miller is accurate in his assessment.
So what does this mean for the 2016 season?
Again using fWAR, I took the top-10 bullpens so far this season, included their current record, as well as their projected end-of-season record according to our projections.
|Team||ERA||xFIP||fWAR||Record||nF Proj. Record||nERD (Rank)|
|White Sox||1.52||3.35||0.9||10-5||82-80||0.54 (7)|
This table is more of a mixed bag than the previous one. The New York Yankees have the best bullpen fWAR, but only three teams have fewer wins than their five.
The Chicago White Sox already have 10 wins -- third most in baseball -- but we project them to finish the season with just 82.
Regardless, 6 of these 10 teams have a top-10 nERD and a projected winning record, so maybe we can use this information to find out which team will have the best bullpen at year’s end, and more importantly, who will win more games than expected.
It’s likely too early in the season to put significant weight into bullpen fWAR, but don’t be surprised to see the Yankees, Chicago White Sox, and Baltimore Orioles all surpass their low projected win total.
Especially for the Yankees with this guy coming back to what has been baseball's best bullpen so far this season: