The bullpen usage chart

As I’m writing this, I’m nearly ready to leave for my summer trip. I’ll leave on Aug. 19, I will be in San Francisco for the PITCHf/x Summit on the 28th, and I’ll be back home on Sept. 2. That’s the time when the races will start to get hot.
And when things get rolling I want everything I need to properly follow the unfolding of the games.

Pitching is always a big part of the baseball equation and when the divisional and wild card races are at their climax, we surely pay attention to the rotation turns even more than we normally do during the season. When the American League Central was going to the final showdown last year, the late match-up against the Royals would seem to favor the Twins, had they not had to face would-be Cy Young winner Zack Greinke on Game Two of the series. (They erupted for four runs in the sixth after having been held scoreless by the Kansas City ace).

Rotations usually bring few surprises down the stretch, as managers consider going with a four-man crew rather than stay with the usual five-unit squad (quality vs rest), and hardly anything more.

Bullpen management can become trickier at the end of the season for a team that’s still in contention. Sure, more arms are available thanks to expanded rosters, but with every game counting, putting the ball in the hand of an unproven pitcher might not be a comfortable idea. When you must win every day, you would probably even skip the middle relievers and bring in your ace early if the game is on the line; on the other hand, you would also have a quicker hook with your starters, since you can’t afford to let the game get out of reach. So you win a big one by pushing the right buttons today and you find yourself short of fresh quality arms for the next couple of games.

If you are thinking I’m going to come up with a great formula to optimally manage the bullpen in September, I’m afraid you’ll be disappointed. In fact, what I’ll produce in the following paragraphs is just a sheet I would like to have in my hands when watching important games in September.

I’m sitting on my couch watching the ballgame and the manager signals for the bullpen, and I wonder why he did not bring in that other reliever. Maybe the announcers said it and I wasn’t paying attention, maybe they didn’t say, that the reliever I’m looking for has pitched four days in a row and is hardly available today.

A great resource is already online which addresses this problem. It’s the Bullpen Usage tool at Daily Baseball Data.

This wonderful tool shows the bullpen usage for the last one to seven days (how many is your choice), and you have the details of each relief appearance just one mouse click away. It’s nearly perfect. The only kink is that it lacks the immediacy only a chart would bring—and here I am to address this.

Let’s get back to the Tigers-Twins 163rd game last year.

Here’s how Detroit’s arms options looked like on the eve of the big game.

Above the thick line you see the starters, defined as the pitchers who, during the season, started at least half the games they appeared in. The choice was made in order to have the production of such charts automated. Tweakings are needed to:
{exp:list_maker}get rid of pitchers who have played for the team during the season, but are not available anymore (see Dontrelle Willis).
update the roles (starters/relievers) according to how the pitchers are used at that particular time (see Nate Robertson). {/exp:list_maker}

In case you are wondering how pitchers are sorted, it’s by their WAR (FanGraphs‘ values). Thus you have the starters on top (from best to worst) and the relievers below the thick line (again, from best to worst).

Here is Minnesota’s situation entering Oct. 6, 2009. Again, the rotation has changed a bit during the course of the season. (Francisco Liriano, back from an injury, had only an aborted start on Sept. 27, while Brian Duensing moved from the pen to the rotation).

Now let’s look at the charts side to side. They are tiny, so we can’t go into details, but the shading should suffice to inform us the Twins (left) had the most worn pitching staff.

If you scroll back to the bigger charts (or just click to enlarge the small ones) you see Minnesota had used both Carl Pavano and Nick Blackburn on short rest and had only Scott Baker with a full four days rest for the big game, having had Duensing throw 11 pitches of relief-ball in Game 162.

On the other hand, the Tigers had Rick Porcello more than rested, and Nate Robertson also idle for four consecutive days.

Homestretch: The 1967 AL Pennant Race, Part 3
A tight race shows no signs of letting up.

With Oct. 5 available to everybody to get a good rest, the pitch load on Minnie’s pen in the previous days was probably not a big factor on the playoff game, even when we know (after the fact) that a lot of relief support was needed in the 12-inning affair.

On the other hand, entering the game against the Royals on Oct. 4, the 57 pitches in the last three days on team stopper Joe Nathan‘s shoulder might have loomed large on Ron Gardenhire‘s game plan (the bats kept troubles away as Minnesota took a 7-0 lead after three).

Those days are gone. A new season is getting close to its final month. This weekend the Giants and the Padres will battle for the National League West leadership, so here is the usage status of their pitching staffs (as of Wednesday; Giants on the left, click on the thumbnails to enlarge).

When I get home in September I’m going to watch a few games with charts like this printed and at an arm distance.
Would you like a copy too?

References & Resources
Pitch count data provided by FanGraphs.

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This is fantastic


I would hope that ML Managers have a chart similar to this that includes number of times a pitcher has warmed up in the pen(I am sure the Mets don’t have any such chart however)in order to keep accurate track of what their pitchers are doing.


This is great stuff.

As a Twins fan, this brings back fantastic memories from the 2009 season.

I would love to get these charts in my hands from here until the conclusion of the 2010 season.