What Can We Expect From Corey Seager in 2016?
It would probably be an understatement to say Corey Seager made the most of his brief time in the big leagues last year.
The 21-year-old made his Major League debut in September with the Dodgers, posting a .337/.425/.561 slash line with four home runs in 113 plate appearances. His 175 wRC+ was second in baseball among players with at least 100 plate appearances (only Bryce Harper and his 197 wRC+ was better).
Obviously his 175 wRC+ is due to regress, especially since it was in part the product of a silly .387 batting average on balls in play.
Expecting this again would be foolish, but Seager did also acquit himself well in terms of stats that become reliable. He posted a 12.4% walk rate and a 16.8%, which were both better than the National League averages of 7.7% and 20.9%, respectively.
Also, while his overall offensive output was unsustainable, it probably also wasnâ€™t that surprising, given his .307/.368/.523 slash line in 1704 minor league plate appearances.
Seager is now expected to be the Dodgersâ€™ starting shortstop, so by looking at his minor league track record and brief cameo in the bigs last year, we can hope to get a glimpse of what to expect this season.
A Lot of Swings, A Lot of Walks...Huh?
While watching Seager mash baseballs would cause your jaw to drop, taking a closer look at his walk and strikeout rates would make you scratch your head.
His aforementioned walk and strikeout rates were excellent, and both stats stabilize fairly quickly (at around 60 plate appearances for strikeouts and 120 plate appearances for walks, according to Russell Carleton).
His success here was somewhat unexpected, though, especially in terms of walks, as he posted an 8.5% walk rate and 18.4% strikeout rate in the minors.
In fact, his 12.4% walk rate in the majors last season marked his career-high as a professional, surpassing his 10.9% mark as a Single-A player in 2013.
Things look even weirder after looking at Seagerâ€™s plate discipline numbers with the Dodgers, as he swung at 51.6% of all pitches and swung and missed at 11.2% of them, above the league averages of 47.8% and 10.1%, respectively, according to FanGraphs.
Itâ€™s a very odd combination, given the fact that we would expect a player who swings and misses frequently to also strikeout frequently while not also not walking at an exceptional rate.
In light of these swing rates and his minor league track record, it would probably be best to expect some serious regression in terms of Seagerâ€™s strikeout and walk rates.
Can the Hits Keep on Coming?
Considering this potential decline in walk and strikeout rates, can we expect Seager to continue to hit the ball for both average and power?
Itâ€™s a given he will not run anything near a .387 BABIP again, but his minor league stats and prospect pedigree suggests he can continue to have success at the plate in the big leagues.
Seager was recently named Baseball Prospectusâ€™ top prospect of 2016, and prior to the 2015 season, FanGraphsâ€™ Kylie McDaniel gave Seager a plus grade in terms of future raw power and above average grades in terms of both his future hitting and future game power tools.
In the minors, he ran a .348 career BABIP, but this might imply he simply owned minor league pitching, as opposed him to being the recipient of good fortune.
Anthony Boyer of the Astros blog Crawfish Boxes found that as younger players advance through the high minors, they tend to run a higher BABIP than their older counterparts, noting that this may suggest â€œminor league BABIP can serve as a pretty strong indicator of talent level.â€
In terms of his power, this was on display during Seagerâ€™s big league cup of coffee, as he posted a .224 isolated power rate (extra bases per at bat; the NL average for non-pitchers was .150 last year).
This is in line with both what the scouts say about his power and his minor league track record, as he posted a career ISO of .217 in the minors.
As with his walk and strikeout rates, though, a closer look here raises some eyebrows about how sustainable his approach during his September cameo was.
Mike Podhorzer of FanGraphs notes that â€œSeager was able to post an ISO above .200, despite hitting fly balls at just a 26.6% rate.â€
This is very strange, given that his ISO was well above the big league average, his fly ball rate was well below average (it was 33.1% for non-pitchers in the NL), and fly ball rate has a very strong correlation with ISO (itâ€™s obviously harder to get an extra base hit on a grounder).
A home per fly ball rate that was nearly double the NL average (19.0% vs. 11.0%) probably helped here, and while HR/FB is more consistent for hitters than it is for pitchers, his elevated rate screams outlier.
Carleton found that HR/FB stabilizes for hitters after about 50 fly balls, while Seager put 21 balls in the air last year. While it was a good sign he did not hit a single infield fly, the sample is still small enough that we can infer his home run rate was more a product of random variation than true talent.
Considering what we know about Seager as a prospect, we can probably still expect to him be an above average power hitter in the big leagues, but another season with an ISO north of .200 might be pushing it.
What Do the Projections Say?
Perhaps unsurprisingly, the projection models currently available expect Seager to have a very good season, while also forecasting the regression we expect in terms of strikeouts, walks and power.
Here is what Steamer and ZiPS (both available at FanGraphs) have in store for Seager in 2015:
ZiPS is higher on Seager, though both have him posting similar batting averages and on-base percentages. ZiPS forecasts more power and more playing time, so the model projects him to be more than a win better than Steamer does (though keep in mind that Steamer projects fWAR, while ZiPS uses a different WAR model).
He wonâ€™t post the per plate appearance numbers he had last season, but Seager still has a ton of upside and will be one of the more fun young players to watch this year.