The lingering spectre of regression

The Mariners' 2014 season was great. As Jeff Sullivan pointed out earlier today, of all the fans of teams in the AL West, we got to end the season feeling the happiest: Texas and Houston sucked, while Oakland and Anaheim were immediately eliminated from the playoffs in soul-crushing fashion. The Mariners, on the other hand, exceeded expectations and ended the season on the highest non-playoff-victory note possible.

There's a thing about exceeding expectations, though. Sometimes it represents a legitimate plateau leap, but far more often it represents a whole lot of luck. Because of this, when projecting future performance, it's important to consider the possibility of regression to the mean. And considering regression, in the case of the 2014 Mariners, is... not pretty.

Negative Regression Candidates

Kyle Seager

This one's no fun, but it has to be said: if I were a betting man, I'd bet that last year was Kyle Seager's career year. In 2012 and 2013, Seager was a solid all-around player: decent plate discipline, decent power, decent baserunning, and decent defense at a position of middling difficulty. That sounds uninspiring, but very few players bring a truly complete all-around package like that to the table, and his performance made him a well above-average player in each year.

In 2014, though, Seager broke out. Great! Unfortunately, he broke out in one of the least predictive ways possible: on defense. Whereas pre-2014 Seager had been a competent gloveman at the hot corner, in 2014 his results were great. UZR and DRS both credited him for 10 runs above average, and the scout's eyes agreed, to the point where Seager's in legitimate contention for a gold glove.

The thing is, defensive metrics deal with deceptive sample sizes. Seager participated in 422 plays last year, but of those, 361 were defined by Inside Edge as "routine" - that is, made 90-100% of the time. The plays that really differentiate defenders are the remaining 15% of opportunities. Unfortunately, a third baseman is only likely to get 60 or so of those in a year, which is a super small sample size. Seager's early-season slump this year lasted for about 75 plate appearances. Saying now that he's made a plateau leap as a defender is about as legitimate as saying then that he'd cratered as a hitter, i.e. not very. I'm hopeful for Seager's continued defensive success, of course, but like Steamer, I'm of the opinion that when projecting 2015 we should probably knock a win or so off of his projection to account for defensive regression.

Chris Taylor

Every Pitcher Not Named Hisashi Iwakuma or Charlie Furbush

Here's the real problem. The Mariners' clear strength in 2014 was their superior pitching staff, which posted to the second-lowest ERA in the major leagues. Sadly, this success appears more or less totally unsustainable. Red flags are everywhere. Tom Wilhelmsen's 2.27 ERA came on the back of a .204 BABIP and an 82.3% LOB rate; he's an interesting long man but hardly the shutdown reliever he was this year. James Paxton's first ten major league starts were a revelation, but his peripherals suggest a solid #3 starter going forward much more than they suggest an ace. Taijuan Walker's not going to do the whole 2.61 ERA thing again, even if he manages to hang on to his improved control. Dominic Leone won't hold 5/6ths of his baserunners forever. The minor end-of-season injuries to Roenis Elias and Hisashi Iwakuma are worrying. Even Felix himself isn't an exception here: he hasn't historically been a low-BABIP guy, and while his GB% spiked this year as he increased the percentage of his pitches thrown down in the zone, a .258 BABIP is a little silly. So is a 2.14 ERA.

Some of the Mariners' pitching staff's success can be attributed to defense, specifically the improved work of the outfielders under new coach Andy Van Slyke and Mike Zunino's work behind the plate. A lot of it can be attributed to the fact that the Mariners' pitchers are really, really good. King Felix is the best starter in the AL, and only two teams in the Junior Circuit (Chicago and Detroit) boast 1/2 punches that stack up with Seattle's. Their bullpen has so many legitimately excellent right-handed relievers that they're probably going to have to trade one this winter just to make room for Carson Smith. But, like any extreme performance, the Mariners' 2014 pitching success was part skill and part luck. And you should never bet on luck to continue.

So, uh, that's the bad news. Almost all of the Mariners' best players in 2014 are probably going to get worse next year. Which is sort of the definition of regression. Still, on a happy note, regression works both ways...

Positive Regression Candidates

Austin Jackson

I don't want to go too in-depth here, because Andrew has an article on Jackson coming out this Monday. So, the short version: Austin Jackson has zero home runs as a Mariner. Austin Jackson had double-digit home runs in each of the three full seasons before he became a Mariner. Austin Jackson's 2014 HR/FB was 2.6%. Over the last five years, Willie Bloomquist's HR/FB is 3.0%. Jackson's power outage down the stretch is a big reason why the Mariners missed the playoffs, but he's got an entire winter to replace the blown fuses.

Brad Miller

Brad Miller is a better hitter than Chris Taylor. Behold, a SW%/CT%/ISO table:

Taylor narrowly wins plate discipline - despite similar K and BB rates, he has a higher rate of swings on strikes and a lower rate of swings on balls - but the other core skills of hitting slant way in Miller's favor. He makes more contact, and the contact he makes is harder. The difference at the plate going forward should probably be somewhere between 10 and 20 runs over a full season (which, interestingly, almost exactly cancels Taylor's advantage on defense).

So, if the peripherals are so slanted towards Miller, why were the 2014 results so slanted towards Taylor? BABIP, more or less. Taylor's was .398; Miller's was .268. BABIP, of course, is notoriously unreliable and almost certainly likely to drive upwards regression for Miller. In fact, it already kind of has. Almost all of the damage to Miller's line was done in the first half of the season, when he put up a .246 BABIP despite an xBABIP of .289. In the second half, his BABIP was .333. Voila, a 122 wRC+ shortstop.

In Brad Miller and Chris Taylor the Mariners have a pair of very different shortstops with very similar overall value. Miller is that rarest of beasts: a shortstop who can hit and play acceptable defense. Taylor can't hit nearly as well, but his glovework is good enough to make up for it. It'll be fascinating to watch the Mariners choose between them next spring. Unless, of course, they trade one... which is a discussion for another day.

Mike Zunino

Towards the end of the season, I started tracking a hilarious Mike Zunino statistic: HBP - BB. Zunino finished the year with an HBP-BB of 0, putting him in pretty remarkable company (where by "remarkable" I mean "terrible"). As you might guess from his low walk totals, or from having watched him hit ever, Zunino's 2014 plate discipline was some of the worst in the major leagues. He struck out a third of the time, while walking a thirtieth of the time. That's crazy! That's only very slightly better than the average NL pitcher! That's almost certainly going to regress.

The thing about extreme performances is that they don't tend to last very long. Over the last sixty years, ten hitters have had more HBP and HR than unintentional walks. No one has ever done it twice. So, hey, Mike Zunino might be even more special than we thought! But probably not. Probably he'll regress. His HBP will drop, and his BB will rise, and his K rate will fall, because when you're the single worst hacker in the league there's really only one direction you can go.

So yes, there is some hope for improvement in the lineup. Jackson, Miller, and Zunino should be better next year than they were last year. Unfortunately for the Mariners, Miller's ascendance is likely to be paralleled by Taylor's decline, and Zunino and Jackson improving won't make up for the entire pitching staff adding half a run to their ERA. As a group, the returning 2015 Mariners are likely to perform worse than they did last year.

Luckily, the returning Mariners won't be the only Mariners. If the current M's (plus replacement-level signings) would be an 83-84 win team next year, the Mariners have all offseason to find a way to add those remaining six wins to get into the playoffs. Rumors have connected them to Victor Martinez, Yasmany Tomas, and a host of mid-tier starting pitchers, which is exactly where they should be looking. If Jack Z and the rest of the Seattle front office are aggressive about adding talent this offseason, the Mariners can overcome the spectre of regression and surge into playoff position for 2015. If they aren't, well... while calling this winter "do or die" would be a gross exaggeration, calling it "do or miss the playoffs again and also lose your jobs" wouldn't be.

Hint, hint.