Previously in Leaderboarding: 100-mph pitches | Relievers stranding runners | Quality starts | Hitters in 0-2 counts | RBI percentages | Taking the extra base | Looking strikeouts |Pitch-framers | Best hitting pitchers | Arencibia All-Stars
Since the topic of the day here at Eye On Baseball is relievers, let's devote this episode of Leaderboarding to their efforts. Specifically, let's look at which relievers, on average, pitched in the tightest spots throughout the 2013 season.
To do this, we'll turn to a statistic called "Leverage Index" (LI). LI, by taking into account things like the score, the number of outs, runners on and the inning applies a number to the importance of a given situation. Not taken into account are "macro" considerations like the team's record or place in the standings or month of the calendar.
LI is scaled so that 1.0 is a situation of average importance. Anything less than 1.0 is less important (a big lead or big deficit in the late innings, for instance), and anything more than 1.0 is more important (close game, late innings, for instance). For some perspective, know that merely 10 percent of game situations have an LI of 2.0 or greater. In other words, those are the most fraught situations.
At this point, you can probably guess that, when it comes to pitchers, closers tend to have higher average LIs than do starters or long men or even middle relievers. After all, rarely do you see a closer enter the game in a non-save situation. While there's nothing particularly perilous about, say, a three-run lead with three outs to go, the closer in the main tends to get his work done when the game is still in doubt.
As such, you're going to see a lot of closers on the list of highest average LI of 2013. Let's check out that list now ...
Avg. Leverage Index
High-leverage appearances/total appearances
As you can see, Sergio Romo of the Giants lords over all in terms of LI in 2013, and every one of the top 10 cleared the 2.0 mark referenced above. In terms of high-leverage (i.e., important or high-pressure) outings as a percentage of total appearances, Jim Johnson of the Orioles comes out on top, both on this list of highest LIs and across MLB as a whole in 2013.
Of course, some will point out that Romo pitched for a team that was squarely out of contention for much of the season. If we take a look at the relief ace who best combined excellence, in-game leverage and team relevance, then we'd probably turn to Greg Holland of the Royals, Craig Kimbrel of the Braves, Joe Nathan of the Rangers or Baltimore's Johnson.
Given the tight margin endured by Texas (they were of course part of the AL wild card play-in game), it's fair to say Nathan probably thrived under the most pressure in terms of game situations and the standings. While Kimbrel was MLB's best closer in 2013, bear in mind that his Braves prevailed in the NL East by a healthy 10 games.