Here's hoping Steven Strasburg's great game last night is indicative of great things to come. But how about some context after the excitement from his hyped, and admittedly very exciting, debut has died off? After all, how many wins will Strasburg really be worth to the Nationals? Answering this question proved to be a lot harder than I anticipated, but, several rushed assumptions later, here are my projections:
My first question was how much better will Strasburg be than the pitchers who would be playing in his spot had he not played this year? That is, will Strasburg better the collective efforts that various other Nationals pitchers would have made in his absence? After reading Davenport and Woolner's insightful article on Bill James' famous "Pythagorean Theorem," I decided to use the "Pythagorean method" which the authors employ at the end of the article. For an individual pitcher, the Pythagorean method requires only runs scored and runs allowed during a pitcher's season, and that pitcher's decisions (the games pitched by a pitcher that end in either a win or loss) to predict what his record "should" be.
I will spare you the details, but will tell you that I used some assumptions about how the Nationals offense/defense/pitching would perform and took various other potentially dubious shortcuts to get the necessary inputs.
For Strasburg's numbers, I relied upon this article from the Hardball Times, except for IP, which I thought was too low. I also had to make my own predictions about which pitchers would be pitching in Strasburg's position. I decided that roster moves and managerial decisions would have lead Craig Stammen, John Lannan, and some third pitcher (Jason Marquis, Luis Atilano, J.D. Martin, Jordan Zimmerman or someone comparable) to fill the Strasburg void.
After all this, I came out with these numbers: Strasburg will end 2010 with a 9-4 record and his replacements would have ended at 6-7. But this is not the end of the story. First of all, all that work for a measly W-L record was infuriating. Secondly, it does not tell the full story of how much the Nationals will benefit from Strasburg. After all, the above projections are only individual W-L records, not team W-L records.
Using very similar methods to those above, I predicted that the Nationals would go 12-8 in the 20 games Strasburg is projected to start while they would have gone 10-10 with his replacements pitching. Note that there is a difference in the number of wins between the individual records (9 wins versus 6 wins) and the team records (12 wins versus 10 wins). The different wins are not a mistake; they are mostly due to the average Nats bullpen and offense, both which are coincidentally averaging about .488 runs/IP, and the slightly better than average Nationals starters (a collective 0.55 runs/IP). Because of this, in the games where the starter does not get a decision, the model predicts the Nationals to go about .500, that is, either 4-3 or 3-4.
Finally, what does this mean for the overall record of the Nationals? In my model, the Nationals are projected to go 76-88 without Strasburg and 78-86 with him. A net of two wins is good, but not good enough to lift the Nationals into playoff contention. This speaks to the limited impact one player can have, while it is also a very encouraging sign for an organization coming off of two 100+ loss seasons in a row. With the signing of Bryce Harper, several other talented prospects (http://thenatsblog.com/federal-reserve/federal-reserve/the-nats-blogs-updated-top-prospect-big-board.html), and a good core of hitters, the Nationals could be in contention very soon. And if Strasburg keeps averaging 2 Ks an inning, maybe even sooner.