And now the moment you’ve all been waiting for: the Natstradamus projections for the 2015 season!
This year, the projection comes with a major caveat: If Ryan Zimmerman is no worse than a league-average defensive first baseman, the Washington Nationals are projected to win between 95 and 98 games.
Just to refresh your recollection (because Lord knows I need to refresh mine every year), I use a pretty simple projection system to come up with the Nats’ won/loss totals for the year. The whole thing is based off Bill James’s Pythagorean Expectation, and it’s a satisfyingly intuitive way to figure out how good your team is. In baseball, you win if you score more runs than you allow. The Pythagorean Win Expectation model reflects that.
Imagine the whole baseball season compressed into two halves of one inning at Nats park. First, we need to fill up the lineup card of players. Then, we need to know who these players are–I use a four-year trailing average as the basis for these calculations. Then, we need to figure who plays where and when. This is the greatest acknowledged weakness of my system, as I have somewhat arbitrarily assigned playing time based on my impressions of injuries, etc.
At the top of the inning, the visiting teams come to bat. The result of that half-inning will be Runs allowed. Any upper-deck crank will tell you that there are two ways you can allow a run, generally: by pitching badly (giving up tons of walks and homers) or by fielding badly (not getting to balls hit in the gap, dropping fly balls, committing errors). The same upper-deck crank will tell you that you can get out of the inning with good pitching (striking everyone out) and great fielding (robbing home runs, showing ridiculous range, gunning down runners with your arm). In my model, base pitching runs allowed off a pitcher’s FIP (I also use xFIP as an alternative, which normalizes pitcher home runs allowed to a league average home-run/fly-ball rate). Defense is handled by UZR, which handily expresses defense as the number of extra runs allowed or saved.
At the bottom of the inning, the Nats come to bat: time to score some runs. I use Weighted Runs Created for each batter. Since that’s a counting stat, I divide that by the number of plate appearances over the last four years to get the number of runs created per plate appearance. I multiply this by the number of projected plate appearances (an everyday player will get about 600 plate appearances). That’s the number of runs on the board.
When that’s over, I come to some conclusions.
The 2015 Nats pitching staff is projected to allow between 530 (using FIP) and 562 (using xFIP) runs. The 2014 Nats actually allowed 555 runs–and we were already amazed at how good the pitching was last year.
This is a good thing because there is too much uncertainty about the defense to have any real confidence. UZR is notorious in that it needs a pretty big sample size to stabilize–the rule of thumb is that 3 years’ worth of data for an everyday player is what you’d need for the stat to be of any real use. Unfortunately, Ryan Zimmerman, first baseman, is a relatively new creation. His limited time at first base resulted in a comically bad UZR/150 (i.e., what UZR would be if he played 150 games at first base for a year) of -109.1. If true, it would mean that Ryan Zimmerman’s first base defense would be costing the Nats over 20 more runs than he would stand to get them at the plate (~88, by my calculations). That’s hard to stomach. If we follow the model blindly, though, we end up with the defense costing the Nats’ excellent pitching just over 97 runs. If we back off and assume Ryan Zimmerman is at least a league-average first baseman, the defense improves significantly, actually saving just under 12 runs.
So, if you think Ryan Zimmerman is a 100-run liability at first base (and I doubt very much that this is the case), the pitching and defense combined concede between 627-659 runs (totals not seen since 2011, when the Nats allowed 643 runs). If you think Ryan Zimmerman is a league-average first baseman, the pitching and defense combine to allow between 518 and 550 runs (As good or better than the 2014 Nats).
Turning now to the batting, things are more straightforward. The model projects the Nats will score 652 runs. This is lower than last year’s observed total of 686 runs. The projection reflects my pessimism regarding Rendon’s playing time and the speed at which Span and Werth can return to the lineup. I will be very happily proven wrong on this point, though.
Add it all together, and you end up with 95 to 98 wins if Zim is at least a league-average first baseman. If he is the nightmare that the tiny and highly unreliable sample of data UZR has to work with, things are much less rosy, with the Nats winning between 80 and 84 games, and likely missing the playoffs.