What the Madison Bumgarner injury means (in numbers)

Earlier today, shocking news surfaced for the San Francisco Giants and their ace pitcher, Madison Bumgarner:

The Giants’ left-handed ace sustained a sprained left shoulder and bruised ribs after being involved a dirt bike accident on the team’s day off in Colorado on Thursday, the club said.

That’s from an Andrew Baggarly post.

Losing Bumgarner for any amount of time is a crushing blow to the Giants’ playoff chances. Bumgarner has been the model for consistency and dominance since he became a full-time starter for the Giants in 2011. There are few pitchers in baseball that are a lock to throw 200 innings each year and post WAR totals of 4-5 wins; Bumgarner was among them. Not to mention the general attitude that Bumgarner plays the game with and it’s easy to see how much the Giants will miss him while he works on getting healthy.

But, the question is raised: “Just how much will the Giants miss Bumgarner?”

First, a few assumptions:

  1. The Giants, as projected by FanGraphs, are currently on pace for an 83 win season. We’ll use this as our starting point.*
  2. We’ll speculate that Bumgarner would be worth 5 wins over a full season in 2017; that’s pretty much in line with his projections and recent history.
  3. We’ll assume that the Giants will have three methods to replace Bumgarner: (1) with a 0 WAR pitcher (purely replacement level production); (2) with a 0.5 WAR pitcher; and (3) with a 1 WAR pitcher.

Using those as starting points, we can calculate the loss of Bumgarner’s value over those three levels (with 0 WAR, 0.5 WAR, and 1 WAR replacements). Then, subtract that from the remainder of the projected 83 wins and you get the following adjustments.

Games Missed Win Adjustment (0 WAR) Win Adjustment (0.5 WAR) Win Adjustment (1 WAR)
10 83 83 84
20 82 83 83
30 82 83 83
40 82 82 83
50 81 82 82
60 81 82 82
70 81 81 82
80 81 81 82
90 80 81 81
100 80 80 81
110 80 80 81
120 79 80 80
130 79 79 80
140 79 79 80

You can plug in your preferred numbers and get an idea of what the team’s win record would look like. If Bumgarner misses 80 additional games on this season and the Giants get 0 WAR level production from Bumgarner’s replacement? That drops the Giants to an 80 win team. If he somehow misses just 60 games and the Giants get 1 WAR level production from his replacement, then the Giants would drop to an 82 win team.

Things really look bleak at the 120 games missed mark and beyond, essentially the rest of the season for Bumgarner. If Bumgarner were to miss the remainder of the season, or most of it, the Giants drop to a high 70s win total. That would put them much closer to the Diamondbacks and Rockies in terms of projected win totals for 2017.

5 WAR pitchers don’t grow on trees and the Giants’ replacements for Bumgarner — outside of Tyler Beede — aren’t exciting. Or, good, really. And while I’m a big fan of Beede, you can’t expect him to do what Bumgarner can do. He’s still working his way through AAA and he’s always projected as more of a mid-rotation guy than staff ace. It’s not a dig towards Beede but Bumgarner is just that good. Just that special.

Of course, things shift around if you play with our assumptions: What if the Giants are more like a 86 win team? What if they find better than 1 WAR production from Bumgarner’s replacement? What if Bumgarner somehow only misses a brief amount of time? You can adjust things where you’d like, but the math is still quite ugly.

* The Dodgers, by FanGraphs, are projected to finish the season at 93 wins. The Rockies at 80 wins. The Diamondbacks at 79 wins.