2015 Relief Pitcher Ball-in-Play Retrospective – AL

Over the last few weeks in this space, we’ve conducted a ball-in-play based analysis of position players’ and starting pitchers’ 2015 performance, the most recent post featuring an examination of starting pitchers in the AL West. Next, we’ll take a similar look at 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 manners 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 division 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 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’.

Obviously, 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-five of the 28 pitchers listed had K rates over one-half STD higher than the starters’ league-average K rate, and 24 of the 28 were 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

What’s it take to be an elite reliever? Massive K rate, at least a near-average BB rate, and elite contact-management ability would about sum it up. Andrew Miller, Koji Uehara, Darren O’Day, Zach Britton, Carson Smith, Brett Cecil, Wade Davis, and yes, Mark Lowe qualify for this status. All had K rates at least two full STD higher than league average, respectable BB rates, and Adjusted Contact Scores under 85.

Their contact-management expertise was exhibited in varying ways. Britton and Smith churned out grounder after grounder. Uehara and to a somewhat lesser extent O’Day were pop-up generators extraordinaire. Most of them posted very low liner rates, and those can vary quite a bit from year to year, inviting at least some negative regression.

All but Britton (who allowed very few fly balls) stifled overall authority, and especially FLY/LD authority. Miller, Uehara and O’Day limited overall and FLY/LD authority to over two STD below league average, while Davis (overall), Smith and Cecil (FLY/LD) also were over two STD below in one or the other category.

Narrow “Elite” Misses

Dellin Betances doesn’t quite meet the criteria established for this group (poor command, 93 Adjusted Contact Score), but like teammate Miller, his K rate is so extreme that it nearly drowns all else out. His average fly-ball authority is a bit misleading: he allowed relatively few “can of corn” fly balls, in the 80-95 MPH range, allowing a cluster of hard-hit and another of lesser-hit bloop single-type flies, hurting his Adjusted Contact Score. A healthy Betances joins the elite soon. Cody Allen is another narrow miss. His liner rate should regress downward, and his BB rate isn’t that far out of whack.

Luke Gregerson and Huston Street get it done in a slightly different way, but their results are in the elite range. Their K rates don’t stand out in this company, and Street’s BB rate doesn’t measure up to the other non-flamethrowing types. Their Adjusted Contact Scores (71 for Gregerson, an AL-best 58 for Street) are exceptional, however.

Gregerson posted an extreme grounder rate, and his liner rate was very low, carrying some near-term regression risk. He allowed harder than average fly-ball authority, but simply didn’t allow enough balls to be elevated for it to matter much. His 56 “tru” ERA- outpaces his 77/69 traditional ERA/FIP marks. Street is an even more interesting case. He allows plenty of fly balls, but very few of them are well-hit. About 25% of fly balls are hit at 100 mph or harder; under 10% of those allowed by Street in 2015 were. FIP misses this skill: his “tru” ERA of 57 was far better than his traditional ERA/FIP marks of 83/95.

Youngsters with Elite Potential

Josh Fields showed an elite K rate and contact-management skill last season, though his command remains a significant concern. His pop-up rate was second only to Uehara among this group, and he held fly-ball authority to a reasonable level. Keone Kela also showed significant promise, with a “red” K rate, an average range BB rate, and an 80 Adjusted Contact Score thanks to a strong grounder tendency. He’ll be asked to accept a more highly leveraged role in the Ranger pen this season, and it will be interesting to see how he responds.

Roberto Osuna, like Fields, is another extreme fly-baller, albeit one with a lesser pop-up rate. At a very tender age, he’s already successfully closed in the big leagues, and his command is arguably more advanced than Kela’s. As with all fly-ball pitchers, there is risk attached to Osuna, but he can join the elite group with somewhat enhanced contact-management performance.

Closers Who Didn’t Managae COntact All That Well

David Robertson‘s 120 Adjusted Contact Score leaps off of the above table. While it’s partially due to a ridiculous 30.2% liner rate that just has to regress, he does allow higher-than-average authority across all BIP types. His K-BB differential is top of the scale, but it needed to be last year. He has elite upside, but plenty of risk. Like Dellin Betances, Brad Boxberger’s fly-ball-authority suppression was a bit misleading. He allowed a cluster of very well-hit flies, and another of lesser-hit bloops. That pushed his Adjusted Contact Score over 100. His very high BB rate is another hurdle he must clear.

Shawn Tolleson has an extremely vanilla profile for a closer. No “red” in his profile, no go-to pop-up or grounder tendency, ordinary authority management. He can adequately handle a late-inning role, but I can’t see him being a long-term solution closing ballgames. Glen Perkins‘ 89 Adjusted Contact Score wasn’t that bad, but the “red” in his overall and grounder authority fields sure do stand out. Solid K and pop-up rates, as well as reasonable limitation of fly-ball authority kept him afloat, but there are some warning signs here.

Joe Smith isn’t a closer, but he possessed similarly ordinary contact-management ability in 2015. Sure, he induces plenty of grounders, but they’re hit pretty hard, as are the fly balls and liners he yields. He’s an average K/BB guy with average contact-management ability, a valuable, durable back-end pen piece with limitations.

Better-Than-It-Looked Award

Take a look at Fernando Rodney’s line: 123 traditional ERA-, 125 FIP-… 76 “tru” ERA-? How did that happen? Well, that 75 Adjusted Contact Score explains a lot. He absolutely throttled overall and grounder authority, over two STD below league average. Unfortunately for him (and for Mariner fans), virtually every well-struck fly ball he allowed cleared the fence last season; he was much better, and luckier, later as a Cub. His K and BB rates have certainly moved backward since his peak, and those seasons aren’t coming back. Still, he remains capable of holding his own in a late-inning role, and more traditional metrics are likely to treat him more kindly this time around.