Last week, we looked at Justin Smoak's breakout 2017 first half, and established that it was partly due to better outcomes on balls in play (extending a trend started in 2015-16), but mostly due to a much lower strikeout rate. That lower strikeout rate is attributable to a huge turnaround in his contact rate, both in and out of the zone. Of the 3,441 players who've had two consecutive seasons of 250 plate appearances since 2002, Smoak's 2017 gain of 8.5% is the 11th biggest gain in contact.
So the big question is: how sustainable is this? Is it likely to be a new baseline for his performance, a fluke, or something in between? This is the critical factor in determining whether it is a good time to "sell high" now, or continue to enjoy an elite slugger for the next couple years.
At a high level, contact rate is one of the most stable metrics for baseball players year to year. Using that sample of players with consecutive years of 250 PA, the year-to-year correlation is +0.89, which for real world data is about about as close to perfect correlation as it comes. Raising the threshold to 500 PA, the correlation is even higher at +0.91.
This would imply that Smoak's 2017 contact rate should have a high level of carryover into the future. Of course, that's not a very satisfying answer, since by the same logic, nothing close to Smoak's 2017 contact rate should have occurred in the first place. What we really want to know is how well similar "contact gainers" have done in future seasons.
To try and answer this, I looked at the 50 players with the biggest year-to-year gains, so roughly the top 1.5%, with a minimum contact gain of 6.5% (only nine were above 9%). Unfortunately, very few are very good or even reasonable comparisons for Smoak, for various reasons that fall into a few broader categories:
- Young players just breaking into the league who struggle with contact in their initial big league stint, quickly adjust, and then don't look back. For example, George Springer in 2014-15. About a dozen of the contact gainers fit here, unsurprisingly the single biggest group.
- Veterans who had a big down year, then bounced back and reverted to their previous contact trend thereafter. For example, Jonathan Lucroy in 2016-17. About another eight of the top contact gainers fit here.
- Players at the end of their career, who had very short careers, or whose careers ended soon after the beginning of the data in 2002. Basically, this is data problem - there's simply not a baseline to assess the prior talent level or whether it was sustained. About another half dozen of the contact gainers fit in this category.
- Really inconsistent players when it comes to contact. Melvin Upton is the archetype here, with season-to-season contact rates just bouncing all around, so it's hard to discern any real trend. This is the primary disqualifier for a couple players, but a few primarily in other buckets would fit too.
- Finally, just bad/inapposite comparisons. 40-something Ichiro Suzuki in the twilight of his career isn't going to tell us anything. Also some high contact players who had a spike and then fell back to trendline. This bucket had about another half dozen of the contact gainers.
That leaves 13 players. To varying degrees, there are similarities between what these players did and what Smoak has done. So I narrowed it down to a core group of eight, and touch on the others at the end. Below is a table with the players, the year of their contact gain, their age that season, and then their contact rates in the the seasons leading up to the gain, the year of the gain, and the three years afterwards (as applicable):
As a group, it's a remarkably good fit to Smoak: low contact players who dipped a bit leading into the year of their big contact gain. Interestingly, Jason Varitek might be the single closest comparison, especially if one adjusted for higher contact rates a decade ago.
What's really interesting is what happened in the years afterwards. The year after their contact breakout, the gains largely held, dipping only from 80% to 79%. However, on average it dips back down in the years that follow, though not fully back to their worst contact rates. It's a pretty small sample, so there's not much to read into it dropping substantially in year 2 and then bouncing back in year 3. We would expect some age related effect in any event as players move through their late prime into their 30s and decline phase.
Still, it's interesting that half of the players held the gain for one more season, and then saw it slip pretty substantially. Mind you, that would still work out alright for Smoak, especially seeing as he's under control for two more seasons. And even if Smoak went back to mediocre power outcomes like he had in 2013-14, he'd still be a solid regular at first base with strong batted ball outcomes like he had in 2015-16, to say nothing of 2017.
Finally, there's another five players who sort of fit the Smoak profile. For various reasons, I don't think they're as strong a fit as the group above, and overall the succession of contact rates is a little different.
Bonds and Jones are Hall of Fame calibre players, both of whom were high contact to begin with. Ike Davis and Stephen Drew curiously had their batted ball outcomes collapse alongside the contact gains, which is not the case with Smoak and they haven't played much since. Felipe Lopez was still pretty young and didn't have a ton of experience, though was in his 4th MLB season. Overall, they were much more consistent in terms of contact rates - both leading up to and coming out of their gain season. To the extent they are relevant comparisons, it's even better for Smoak.
The overall verdict? Some regression, both to batted ball outcomes and plate outcomes is probably inevitable and to be expected. But there is nothing about what Smoak has done in 2017 that screams fluke or suggests the clock is about to strike midnight.