2015 Relief Pitcher Ball-in-Play Retrospective – NL

Over the last few weeks in this space, we’ve conducted ball-in-play based analyses of position players’ and starting and relief pitchers’ 2015 performance. Last time, we considered AL relievers. Today we’ll present the last installment of this series, focusing on NL relief pitchers. It’s admittedly a little dicey to evaluate relief pitchers in this manner. The sample sizes are much smaller, and filled with more noise. Still, it’s a worthwhile exercise that can show us the different ways in which closers, set-up men, et al, get it done.

First, some background on the process. I identified the 214 relief pitchers from both leagues who yielded the most batted balls in 2015, making sure that all team save leaders were included in the sample. From that group, I selected 28 pitchers from each league for further scrutiny. Pitchers are listed with their 2015 league mates; those who were traded during the season will appear in the league in which they compiled the most innings. Pitchers are listed in “tru” ERA order. For those who have not read my previous articles on the topic, “tru” ERA is the ERA pitchers “should” have compiled based on the actual BIP frequency and authority they allowed relative to the league. Here we go:

First, a little background. The larger group of 214 relievers had a cumulative strikeout rate of 22.2% and walk rate of 8.2%. Both rates are higher than the comparable marks for starters (19.8% and 7.0%, respectively). The larger group of relievers also conceded less authoritative contact than starters, allowing lesser overall (88.02 mph for relievers, 88.46 mph for starters), FLY/LD (91.24 vs. 91.78) and grounder (85.76 vs. 86.30) authority. With regard to BIP frequency, relievers outpaced starters in the key grounder-rate category by 45.6% to 45.2%, and matched them in pop-up rate (3.2%).

The subset of relievers listed above generally represents the cream of the relief crop. Most of the column headers are self-explanatory, including average BIP speed (overall and by BIP type), BIP type frequency, K and BB rates, and traditional ERA-, FIP-, and “tru” ERA-. Each pitcher’s Adjusted Contact Score (ADJ C) is also listed. Again, for those of you who have not read my articles on the topic, Unadjusted Contact Score is derived by removing Ks and BBs from opposing hitters’ batting lines, assigning run values to all other events, and comparing them to a league average of 100. Adjusted Contact Score applies league-average production to each pitchers’ individual actual BIP type and velocity mix, and compares it to league average of 100.

Cells are also color coded. If a pitcher’s value is two standard deviations or more higher than average, the field is shaded red. If it’s one to two STD higher than average, it’s shaded orange. If it’s one-half to one STD higher than average, it’s shaded dark yellow. If it’s one-half to one STD less than average, it’s shaded blue. If it’s over one STD less than average, it’s shaded black. Ran out of colors at that point. On the rare occasions that a value is over two STD lower than average, we’ll mention it if necessary in the text. An especially important note here: the averages to which each pitcher’s performance is compared to the starting pitchers’ average figures. I wanted to compare all pitchers in each league to the same norms, rather than have a moving target, that would in this case make relievers appear to be less dominant than they are.

Before we get to the pitchers, a couple words regarding year-to-year correlation of pitchers’ plate-appearance frequencies and BIP authority allowed. From 2013 to -15, ERA qualifiers’ K and BB rates and all BIP frequencies except for liner rate (.14 correlation coefficient) correlated very closely from year to year. The correlation coefficients for K% (.81), BB% (.66), and pop-up (.53), fly-ball (.76) and grounder (.86) rates are extremely high. While BIP authority correlates somewhat from year to year — FLY/LD authority is .37, grounder authority is .25 — it doesn’t correlate nearly as closely as frequency. Keep these relationships in mind as we move on to some random player comments. Year-to-year reliever correlation coefficients should be expected to be lower than starters’.

As with the AL group, there is a ton of red and black on this table. Relief pitchers are creatures of extremes, mostly positive ones. They have extreme stuff, extreme contact-authority-suppression skills, and even extreme BIP frequency tendencies in comparison to starting pitchers. Of course, they are more likely to completely disappear from the table from one year to the next. They only have to navigate the batting order one time around in most cases, and can push the accelerator to the floor every time out. Twenty-three of the 28 pitchers listed had K rates over one-half STD higher than the starters’ league-average K rate, and 23 of the 28 also had better-than-average Adjusted Contact Scores. Still, there is some interesting pitcher-specific data to discuss here, as well as some fairly large discrepancies between “tru” ERA and traditional ERA/FIP.

The All-Around Elite

As I referenced in my previous AL companion post, elite relievers have a massive K rate, at least a near average BB rate, and elite contact-management ability. Not as many NL relievers meet all of those criteria. The top group is composed of Kenley Jansen, Craig Kimbrel and A.J. Ramos, and if we bend a little on the BB rate requirement, it also includes Aroldis Chapman and Pedro Strop. All had K rates over two full standard deviations above league average and Adjusted Contact Scores of 85 or better.

Jansen represented the NL gold standard in 2015, producing obscene outlier K and BB rates and an extreme pop-up tendency that keyed his 85 Adjusted Contact Score. His ridiculously low liner rate allowed, over two STD below league average, is very likely to regress a bit moving forward. He does carry some risk, thanks to his high fly-ball rate and his relatively ordinary authority suppression ability.

Kimbrel, who has moved on to Boston, was quite underrated by traditional ERA and FIP in 2015. His 62 Adjusted Contact Score was the best of this NL relief group last season, and it was interestingly almost completely driven by the can-of-corn fly ball. Over half of the fly balls allowed by Kimbrel last season were between 85 and 94 mph; such balls are almost never hits, but are hit hard enough not to give him a strong authority-suppression profile. He’ll need to maintain that trait moving forward, as fly balls just above that range tend to find the Green Monster in his new home.

Ramos was a breakthrough success as the Marlins’ closer in 2015, thanks to a very high K rate, a strong pop-up tendency, solid authority suppression and a very low (over two STD below league average) liner rate. All but the last item should hold up moving forward, but some regression should be expected due to upward liner-rate movement as well as the new, more hitter-friendly configuration of his home park, which affects him directly as a fly-ball inducer.

Like Dellin Betances, Aroldis Chapman is so overwhelming that you don’t mind his extremely elevated BB rate. Chapman’s K rate was the best among all relievers in either league last season, and his authority suppression marks were over two full STD below league average across all BIP types last season. His pop-up rate was off-the-charts high, though his Adjusted Contact Score was a very good but not elite 83 thanks to an ordinary (at least in this company) liner rate.

Like Chapman, Pedro Strop’s one blemish on his 2015 profile was an extremely elevated BB rate. His contact-management profile was quite strong, with his 74 Adjusted Contact Score driven by a unique daily double: elevated pop-up and grounder rates. That one will be hard to replicate moving forward. The grounders allowed by Strop last season were quite well struck; of the players listed above, only John Axford allowed them to be hit harder.

Narrow “Elite” Misses

The next group contains ten relievers who didn’t quite qualify for elite status by narrowly falling short on one criterion. Six were a bit less outstanding with regard to K/BB, the other four didn’t quite manage contact well enough. The former group is composed of Drew Storen, Joaquin Benoit, Randall Delgado, Hector Rondon, Mark Melancon and Sam Dyson; the latter, Will Smith, Sergio Romo, Shawn Kelley and Jeurys Familia.

Storen was the only reliever among the group with the nine lowest “tru” ERA marks not to have a K rate at least two STD higher than league average. He posted a strong 75 Adjusted Contact score despite a high liner rate allowed, thanks to a high pop-up rate and strong authority suppression across the board. Ageless wonder Benoit, now a Mariner, had a similar profile, with a relatively unimposing K/BB profile, but an even better 69 Unadjusted Contact Score, with a high pop-up rate and extreme authority suppression across the board. His overall and grounder authority allowed were the best on the above table, over two STD better than average; even better than Chapman.

Delgado, too, fits a similar profile, with even worse K/BB rates, but even better contact-management skills. He posted a 67 Adjusted Contact Score, also keyed by a high po- up rate and strong overall authority suppression. Delgado and Benoit did have unusually low liner rates allowed, and could regress in that area moving forward. Rondon’s K rate was a little low among this group, but his BB rate was one of the best. His 84 Adjusted Contact Score was solid and largely due to a somewhat elevated grounder rate and suppression of fly-ball authority. Almost half of the fly balls he allowed were smack in the middle of the “donut hole,” from 80 to 90 mph.

Melancon’s K rate boldly stands out for its lack of color above, but his very low BB rate and 73 Adjusted Contact Score propel him higher. His grounder rate is the fifth highest of those listed, and is the primary driver of his contact-management performance. Dyson posted an identical 73 Adjusted Contact Score, with an even more extreme grounder tendency, plus a low liner rate that would appear to be ripe for regression moving forward. His K-BB differential is almost identical to Melancon’s.

Smith headed the latter group, with the fourth-best K rate on the above table, but a somewhat lesser 91 Adjusted Contact Score, recorded despite a liner rate allowed over two STD below league average. He allowed fairly well-hit grounders, and pulled off the negative daily double of simultaneously posting high fly-ball and low pop-up rates. Romo’s K-BB differential is one of the best above, but his 95 Adjusted Contact Score doesn’t stand out. That was due in large part to an elevated liner rate, likely to regress moving forward. A high pop-up rate and strong authority suppression across the board (overall and grounder authority over two STD lower than average) helps his cause. Both Smith and Romo are on the shelf presently, illustrating the volatile nature of relief excellence.

Kelley has quietly displayed his understated, near-elite portfolio of skills in recent years. His K and BB rates are strong, even in this company, and his 88 Adjusted Contact Score, driven by a high pop-up rate, is pretty close to elite status. His one blemish is a big one, however: that high average FLY/LD authority mark, second worst on the table above. When Kelley hangs a slider, it goes far, and he does it a little more often than you’d like. Familia is also about as close as you can get to the elite group. Like Storen, he’s not quite in the “red” K rate group, and his 90 Adjusted Contact Score is close as well. His grounder rate is the third best of the group above, though his grounder-authority allowed is rather ordinary. A little cut in his liner rate would also tip him into the top group.

Closers Who Didn’t Manage Contact All That Well

This group includes Francisco Rodriguez, Jason Grilli, Trevor Rosenthal, Jonathan Papelbon, Ken Giles, Santiago Casilla, Jeremy Jeffress, Steve Cishek and John Axford.

Rodriguez had an exceptional K-BB differential and suppressed authority (over two STD below average) across the board, but had a modest 97 Adjusted Contact Score thanks to an elevated liner rate. Grilli had by far the worst “tru” ERA of any NL reliever with a “red” K rate, thanks to a 104 Adjusted Contact Score driven by an over-the-top high liner rate. His BIP sample was the smallest of the above group, so I wouldn’t sweat it too much. Love his high pop-up rate.

Rosenthal’s 93 Adjusted Contact Score is just OK in this company. His best contact-management skill is his pop-up tendency, but his authority suppression was very ordinary, and his liner rate is likely to regress upward. It’s a similar story for Papelbon, who posted a 95 Adjusted Contact Score with a very low liner rate. His K rate (and his raw stuff) is in decline, and his authority suppression is nothing special. The difference between his 2015 traditional and “tru” ERAs is pretty stark.

Ken Giles’ early 2016 struggles make a little more sense in light of the information above. There is nothing special in his BIP frequency or authority profile, and his 107 Adjusted Contact Score is the second highest of those listed. Sure, he’s got a big arm and a big upside, but there is plenty of work to do. Santiago Casilla stifles grounder authority (over two STD lower than average), but he posted a mediocre 102 Adjusted Contact Score due in large part to a high liner rate allowed.

Despite a high 109 Adjusted Contact Score, there are some positives in Jeremy Jeffress’ profile. His grounder rate is the fourth highest of those listed, he squelched fly-ball authority, and his high liner rate should be expected to positively regress. No pop ups, though? Even for a ground-ball generator, that’s a no-no. Steve Cishek, now a Mariner, had no standout BIP frequency tendency, and though he managed authority well, particularly on the ground, could manage only a 98 Adjusted Contact Score. Axford’s 120 Adjusted Contact Score is a bit scary, as the effects of Coors Field are weeded out from that number. His authority allowed is much louder than that of any other listed pitcher.

Better-Than-It-Looked Award

Where did the promising start to Juan Nicasio’s 2016 season come from? Well, the Pirates front office saw some things they liked from 2015, turned him over to Ray Searage, and here we are. He shut down authority of all types last season, especially on the ground (over two STD lower than average), allowing him to post a 94 Adjusted Contact Score despite a very high liner rate allowed. Though his 90 “tru” ERA didn’t match his gaudy 74 FIP, it far outpaced his 103 traditional ERA.

Doing It Without Ks Award

The clear winner in this category is Brad Ziegler. He’s the only “blue” guy in the K rate column above. When your K rate is low, your contact-management ability had better be really good for you to thrive, or even survive. Ziegler posted a strong 65 Adjusted Contact Score, largely due to his stratospheric grounder rate, second only to Zach Britton among relievers we’ve examined this week.

Brandon Maurer also gets a mention here. His K rate is the second lowest listed above, but he suffocated authority of all BIP types, and posted a 68 Adjusted Contact Score. Like Pedro Strop, he pulled off the difficult feat of posting a higher-than-average pop-up and lower-than-average fly-ball rate. That will be tough to duplicate moving forward, but it indicates ability to get weak outs in different sectors of the strike zone.

Well, it’s time to lay 2015 to rest. Sample sizes for the young 2016 campaign remain small, but are now large enough to at least develop some reasonable hypotheses. Plus, the publicly available Statcast data is much more voluminous and detailed this season. We’ll begin to delve into it next week.