Mid Season Pitcher Workloads

At the midway point of the season, it’s always interesting to see how teams are utilizing their pitching staffs. I’ve been examining workloads through the metric I created, called Fatigue Units. This metric accounts for days between appearances, stress during pitching, and time between pitches – you can read more about it here. TLDR; Fatigue Units appear to be a more accurate indicator of “overworked” pitchers than pitches, or innings pitched.

To start off – what does the midway point indicate about a pitcher’s workload? It doesn’t necessarily indicate what the workload will be by season’s end, but it does say that the pitcher has worked hard in the first half. It definitely says that the team has trusted that pitcher, and, that pitcher is very good. Here’s what the halfway point workloads looked like in 2016.

And, here’s what they looked like at the end of the season.

So halfway point doesn’t necessarily indicate that you can linearly extrapolate the workload for the rest of the season, but you do see that 9 of the 15 all start break workload leaders ended up being in the top 15 at the end of the season.

So, how are things looking in 2017?

This table indicates a few things; the first being – The Rockies starters are doing incredible work this year. They are absolutely crushing it, in an environment that has been so traditionally hard on pitchers. It may be that the offence has been so good, the pitchers are being given a bit more leash. Any way you slice it, they’re sparing their bullpen, which will likely be called upon frequently in the second half, as the young Rockies starters get a break from time to time. On the other end of this – you can see that the terrible Blue Jays, Phillies, and Reds rotations aren’t getting overworked, because most of the time – their starters are getting shelled, and are out of the game early.

Now with the Bullpens, you can see some interesting trends;

First and foremost – the Mets are running their bullpen into the ground. They have a signficant lead in fatigue units over the second place team, and a massive lead in back to back appearances from their bullpen pitchers (81 times this year, a pitcher has come into a Mets game having pitched the day before). That seems… drastic. The Brewers are next, with 71 back to back appearances, and then the values seem to level off.

Once again – this is hardly a kiss of death for pitchers. This was an attempt to present a more physiologically representative method of workload demands on pitchers. You don’t need to go add and drop anyone any time soon because of this list – but if it comes down to one hot hand vs. another in your playoff matchups, you might want to go with the reliever with more gas left in the tank.