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The Rockies bullpen has been eked out so far by the Astros for the majors' worst ERA, but have last place all to themselves in FIP. And it's not just a Coors Field thing, it appears; the Colorado relief crew rank near the bottom in xFIP (27th), which helps limits the effect of Coors Field home runs, and SIERA (28th), which uses a park factor.
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Last season Rockies relievers also did poorly in ERA, but were actually at or near league average in the other three statistics. This season, not so much. The loss of Josh Outman (3.25 FIP in 2013) didn't help, and new guys LaTroy Hawkins (3.37 FIP) and Tommy Kahnle (3.98 FIP) have been more good than great. But the difference in performance can be largely staked to the fact that Matt Belisle has gone from very good (3.03 FIP in 2013) to not so good (4.03 FIP), and Rex Brothers has gone from good (3.36 FIP) to awful (5.22 FIP).
Only one Rockies reliever has been very good both this year and last: Adam Ottavino.
| Year | G | IP | ERA | FIP | xFIP | SIERA |
|---|---|---|---|---|---|---|
| 2012 | 53 | 79 | 4.56 | 3.85 | 3.41 | 3.39 |
| 2013 | 51 | 78.1 | 2.64 | 3.15 | 3.54 | 3.31 |
| 2014 | 61 | 55 | 3.76 | 3.17 | 3.27 | 2.74 |
Ottavino's statistics from the last two years are very impressive, and not just as a reminder that statistics like FIP and SIERA are often used well when used together. From 2012 to 2013, a much-improved home run rate drove down Ottavino's FIP and ERA. From 2013 to 2014, something else caused SIERA to go from lukewarm to highly complimentary of his performance.
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So what has made SIERA so impressed this year? It's not batted balls — Ottavino's ground ball rates have lingered in mediocrity throughout his career, and there's nothing special about his fly ball rates, either. Part of the premise of SIERA is that lots of ground balls generally means a higher percentage of those ground balls are playable, and that the higher a pitcher's fly ball rate, the lower his likely HR/FB. So if I told you Ottavino's line drive percentage in his three Rockies seasons have dropped from 26.3% to 21.9% to 18.8%, you should be impressed — but you shouldn't see that as an explanation for Ottavino's SIERA.
Instead, the answer is in Ottavino's improved strikeout rate and walk rate. His FIP has barely flinched from 2013 to this season, but the plate discipline numbers were somewhat masked by a small jump in home run rate (hence the drop in xFIP, as well). And it's not that SIERA whiffs on Ottavino's line drive rate — it's more that the benefit from that is baked into SIERA's higher-than-FIP respect for high strikeout pitchers.
| Year | SIERA | K% | BB% | HR/FB |
|---|---|---|---|---|
| 2012 | 3.39 | 23.9% | 10.0% | 16.1% |
| 2013 | 3.31 | 23.3% | 9.3% | 7.1% |
| 2014 | 2.74 | 25.5% | 6.4% | 8.9% |
The uptick in strikeout rate (and yes, we're only talking about a difference of 5 or 6 Ks given the sample size) has been supported by a return to previous velocity levels. Ottavino throws a changeup only once in a blue moon (fewer this year), and while he also throws the occasional sinker, Ottavino lives and dies with his fourseam fastball and slider, both of which he's thrown at least 42% of the time in each of the last three seasons. Compared to 2013, both of Ottavino's fastballs have jumped up about 2 mph (with the change almost following suit).
Compare these trajectory and movement tables from Brooks Baseball for the last two seasons:
The uptick in Ottavino's fastball velocity could account for a big part of his success, especially given the accompanying change in horizontal movement: almost a full two inches (for the fourseam). Where Ottavino's fourseam used to be more than a run worse than average per 100, it's now pretty OK:
| Year | wFA/C | wFT/C | wSL/C | wCH/C |
|---|---|---|---|---|
| 2012 | -1.11 | 2.87 | 1.58 | 2.60 |
| 2013 | -1.16 | -1.09 | 2.40 | -4.01 |
| 2014 | -0.26 | 1.07 | 0.36 | -26.20 |
One wonders from looking at this whether Ottavino should throw his sinker more than 9% of the time; and while there are some pretty heinous sample size issues with the changeup-runs-per-100 figures, whoa Nellie, maybe that one belongs on the shelf.
The real puzzle is Ottavino's slider. Among relievers, he had the most valuable slider in the majors in 2013 (14.7 PITCHf/x Pitch Value), and it really wasn't even close. That's partly because it was so damned good (2.40 wSL/C is bloody excellent), but also because he threw it so damned often. And the Brooks Baseball numbers above don't show any real change in velocity or movement. What gives? A swing that big in pitch value, at least for a pitch thrown that frequently, is pretty rare.
Maybe Ottavino is tipping the pitch; it was so, so good last season that even if batters knew when it was coming this year, they might have had trouble hitting it. It's also possible that the wider gap between the velocity of his fastballs have made a significant difference in whether batters can discern the slider on its way to the plate. If it's the latter, maybe Ottavino's transition to a short relief role has been a mixed blessing.
Either way, if you've been facing the Rockies this year, Ottavino is the man you least want to see come in from the bullpen. And given the preference of the Rockies to put him in the highest leverage situations (1.47 gmLI), you've been most likely to see him when you've most wanted it to be someone else.
. . .
All statistics courtesy of FanGraphs and Brooks Baseball.
Ryan P. Morrison is a featured writer at Beyond the Box Score, and co-author of Inside the 'Zona, a site on the Arizona Diamondbacks with a sabermetrics slant. You can follow him on Twitter: @InsidetheZona.