Plate Discipline (for Pitchers) – Update #1
(Photo by Frank Jansky/Icon Sportswire)
Last week I laid out the basic principles behind using “Plate Discipline” (PD) metrics to analyze starting pitchers. Now, we can start putting this information into practice! Let’s begin by taking a look at some fan favorites, through the lens of PD metrics. All stats in this article are updated through Tuesday’s games (04/24/2018)
Last year’s #1 pitcher by the metrics (and by everything else), Kluber has a reputation for stinking it up in April, so I thought it might be a useful exercise to check in on him. Lo and behold – he actually is having his usual bad April, you just have to squint through some plate-discipline-colored-glasses to see it. His ERA and FIP are excellent, but his PD metrics are all fairly mediocre compared to his usual self. Overall he’s currently sitting at a B-minus grade. Kluber owners should consider themselves lucky that his (relative) struggles have not hurt their ratios like they usually do in April. Full steam ahead though. That’s just his thing.
Verdict = HOLD
What’s to say about Corbin? He’s simply been flat-out dominant so far this year, leading MLB in K% with a mark near 40, and also topping my PD-metric-based ranking system at this point. His metrics fully support that crazy rate, and he’s been consistent as well. Each of his five starts has been similarly dominant; batters are simply unable to make contact against him right now. The main reason for concern would be his relatively weak schedule so far. He has only played against NL West rivals, and has not pitched against a single team with an wRC+ over 100 yet. There’s a non-zero chance this could end up being a great sell-high opportunity, but, given the utter dominance thus far, I’d probably be more inclined to ride it out.
Verdict = HOLD
Like Corbin, Cole has managed to put up a ridiculous K% near 40 in the early goings. But unlike Corbin, that gaudy rate is not backed up entirely. The metrics suggest he is currently pitching like more of a 30% K guy rather than 40%. This is still very, very good of course, and Cole does look like an ace. But 10% is a significant discrepancy, and it seems likely that his strikeouts will be reduced going forward. Also, he’s currently sporting some very unsustainable LOB% and BABIP numbers. This one is a tough call, because despite the signs of incoming regression, he is clearly someone you still want on your staff. It’s a bummer for Pirates fan, but whatever he’s doing in Houston is working. Just not quite as well as it may seem.
Verdict = HOLD
This is what a breakout looks like. Last year, he made very real improvements in his PD metrics, at the age of 24, but it didn’t really show up in the results. This year he is building on those improvements and taking them to the next level, as he is currently sporting an A+ grade and has the third-best overall score, behind only Corbin and Max Scherzer. Surely he won’t keep at this pace all season, but there’s actually not a single red flag in the metrics. He’s been dominant in each of his five starts, against good teams, and across each of the “Big Three” metrics. I’d be looking to find an owner thinking he’s selling high to take advantage of. Don’t get me wrong, eventually he’ll give up some homers in the AL east. That miniscule HR/9 rate seems very unsustainable. But I think the inevitable correction could end up being much more gentle than expected. It should really help to limit the number of baserunners that score on homers, when you’re striking out 30% of batters.
Verdict = BUY
After two starts against Oakland, Ohtani sat atop the PD metric rankings and it wasn’t even close. But then his next two starts were…not the same. This is a good lesson in small sample sizes, and magnified by playing against the same team in his first two starts. Thanks to those two dominant starts, his overall numbers are actually still VERY good, current sporting an A+ grade. But this is why I would always recommend looking at the plate discipline game logs on Fangraphs for context. From that, it’s easy to see that the dominance all came from those two starts, and his starts against better teams were very lackluster in comparison. Also, his other two starts were shorter outings, so the majority of his data is all against the A’s. Furthermore, he has only pitched 20 innings overall, while most SP are well over 30 by now. Because of this small sample, against mostly just one team, I think it’s too difficult pin a value on him right now. We have no choice but to wait and see.
Verdict = HOLD
If you recall, Weaver stood out to me in last year’s numbers as being the recipient of excellent luck on his K rate. The metrics suggested a rate near 20%, but he managed to put up 29% instead, for one of the largest discrepancies I could find. So far in 2018, his metrics are essentially unchanged from last year, so what’s his K% sitting at? Sorry to break it to you Weaver owners, but that 21.6% mark is right in line with expectations. Going forward, unless he makes some changes, we should expect something closer to this result rather than last year’s performance. His value isn’t exactly the highest right now, but maybe you could try to take advantage of a more “savvy” owner expecting him to rebound based on last year’s FIP or something.
Verdict = SELL
It’s always fun to check on Tanaka, the PD metrics darling. Last year, he graded out as the #2 pitcher in all of MLB when quality-of-contact is omitted. So how’s he doing so far in 2018? Well, it’s basically more of the same story. His metrics are still elite and suggest a 30% K rate, though he’s down slightly from last year. And he’s been hurt by home runs in those tough AL East parks. It’s really a shame he doesn’t play in the NL West or something. I still like him a lot, but you should expect some bumps in the road.
Verdict = HOLD
People are freaking out because his velocity is down a couple ticks, but for whatever reason, so far this hasn’t affected Castillo’s ability to continue putting up elite PD metrics. Typically, it does (see Danny Duffy or Felix Hernandez). Contact% and SwStr% still both see him as the same 30% K-rate guy he was last year; in fact his metrics are slightly up. But somehow, this year so far he’s only striking out 20% of hitters. So it does seem he’s been unlucky with umpires and foul balls not going his way. Normally this would be a very strong “Buy Low” indicator, but, there is also something going on with his “quality of contact” management. How’s this for whatever the opposite of a “fun fact” is called: In 2017, Castillo gave up eight barrels all year, in 89 innings. This year, in just 27 innings he has already given up the same eight barrels. Either the reduced velocity is making it easier for batters to square up his pitches, or, it’s just random fluctuation. Who knows, really. But in the end, I’m going to stick with my process. Quality of contact fluctuates a lot, while strikeouts are supposed to be more reliable, and his metrics still look fantastic, suggesting a lot more strikeouts to come.
Verdict = BUY
The metrics say Nola has not been as dominant so far this year as the results may suggest (ERA = 2.3). He’s striking out just 20% of batters so far compared to 25% for his career, and the metrics support this drop. SwStr% is down and Contact% is up by about the right amounts. Nola typically beats his SwStr%, but so far this year has not shown that ability. So honestly, this is a little concerning despite the pristine ERA. His SIERRA is over four now thanks to that reduction in strikeouts. It seems his success so far is primarily from the quality-of-contact realm. He has done very well there, only giving up 2 barrels on the season. But relying on this always makes me a bit nervous. From scanning Nola’s PD Game Logs, we see: two good games, two bad games, and one average game. So it’s certainly been a mixed bag for him so far, and overall his grade has dropped from the B level to C level. On it’s own, this information might suggest a SELL HIGH situation. However his last start vs the Pirates was the best, by far, of his young season. So I think I’d like to see what happens in his next couple starts. If he reverts back to putting up good ERAs with bad metrics, he might be a “sell high” at that time. But it seems more likely this is just a blip and he will be fine.
Verdict = HOLD
I’d be remiss not to mention the guy who just threw a no-hitter against one of the best offenses in baseball. He’s clearly capable of dominance, as was on display against the Red Sox. Also, his first start of the year vs. the Angels was very strong. However I’m not really sold that he’s turned some corner or something. The three starts in between were mediocre, and as a result his metrics for the whole season are incredibly close to last year’s, and his career numbers (B-minus grade). He’s an above-average pitcher, but there’s simply nothing to really indicate a major breakout. He’s also sporting a 100% LOB and .135 BABIP, both highly unsustainable. He should be a useful fantasy arm pitching in Oakland, but his value is unlikely to ever be higher than it is right now.
Verdict = SELL
K-Rate Discrepancy Outliers
Next up, I’ll present some raw data that should help with players that didn’t make the “fan favorites” cut. Below, I have provided tables showing the biggest under-performers and over-performers on their K-rate so far in 2018. I left the IP threshold rather low here (10 IP) to catch any interesting players.
The methodology I used is as follows:
1) Calculate predicted K% from SwStr% and Contact% using the two rules from the guide
2) Take the average of these two values
3) Subtract the actual K% from this to find the discrepancies
From last week’s guide, we know that some pitchers have demonstrated a consistent ability to beat their metrics by about 4-5 points. So for these lists, I have included all the pitchers with a discrepancy of 5 points or more, as these are most unlikely to be sustainable.
K% Over-performers (luckiest pitchers)
K% Under-performers (unluckiest pitchers)
2018 PD Grades (through 04/24)
Lastly, the table below shows the scores and grades for all SP who have thrown over 10 innings this year. Since that threshold is so low, I included the innings in the table as well for reference. The smallest samples (under 20 IP) are highlighted in red. The methodology for the grades was exactly the same as previously in the guide, but to recap it’s basically a combination of metrics weighted as follows:
- 3 Points: O-Swing%
- 3 Points: Contact%
- 3 Points: SwStr%
- 1 Point: F-Strike%