Who Ya Gonna Call?

Going into the season, the Reds bullpen looked like the second coming of the Nasty Boys. It was not hard to count backwards from the ninth inning: Aroldis Chapman to save, Sam LeCure in the 8^th, Jonathan Broxton or Alfredo Simon in the seventh, and Sean Marshall ready for the occasional lefty. The plan was perfect. If only that plan would have made it out of spring training.

The injuries piled up quickly: Chapman came down with a bad case of ball-to-the-forehead, Sean Marshall’s shoulder injury flared up, and J.J. Hoover has been downright dreadful. At the same time, Mat Latos’ injury forced Alfredo Simon to the starting rotation, further depleting the bullpen.

In light of these injures, the Reds had to rely on AAA talent against MLB-quality hitters. With five games against St. Louis, three at Atlanta, three against Tampa Bay, and four against Pittsburgh in the first month, the Reds would quickly find out if their young bullpen arms were up to the challenge. They weren’t.

Now that we are almost thirty games into the season, it is worth asking: How has our new skipper managed the bullpen? Who does he trust in the most important situation, and who is there just to clean up when the fans are already heading for the parking lot?

To get an idea of whom Bryan Price has turned to this season, here is a breakdown of games and innings pitched:

This is roughly what you would expect given the state of the Reds bullpen this year. Sam LeCure appears to be Brian Price’s favorite arm, using him almost as much as Broxton and Ondrusek combined. The number of games and the number of innings pitched give us an idea of who is getting the call, but not how important each situation is. 

To measure the importance of situations, sabermetricians have developed “leverage” statistics. The “leverage index” measures the importance of each situation during a baseball game. A normal situation is LI 1, while a LI of 2 is considered very important.

“Leverage” is (roughly) calculated by the change in a team’s winning percentage from one play to the next. If a team is ten runs ahead, then giving up a home run and narrowing the lead to 9 will not change the “leverage” index much because the difference between being ahead by 10 runs vs 9 is negligible. If a team is ahead by 1 run in the bottom of the ninth, then giving up a home run has a large impact on a team’s winning percentage. Tom Tango at the Hardball times has a detailed explanation of the index (which, coincidentally, discusses a collapse by Dusty Baker’s Cubs. Stupid Cubs).

Two subdivisions (there are multiple others out there) of this index are relevant to this article:

“gmLI” is the index for how dangerous the situation is when a pitcher enters the game. If Price were to bring in Chapman in the bottom of the 9th with the bases loaded, no outs, and the Reds up 1, gmLi would be around 3.0. If you enter a clean inning, it will be lower. This stat is useful to see whom the manager trusts when the fire is burning, and what reliever Price throws out there when the game is long gone.

“exLI” is how dangerous the situation is when the pitcher leaves the game. By comparing the exLI to the average gmLI, you can tentatively see if pitchers are doing more harm than good (note: if a pitcher ends a game, they will not have an exLI – hence the missing values below).

Normal caveats apply: Small sample size, biased sampling frames, not enough innings for pitchers to return to the mean, etc.  Keep in mind that Sean Marshall is still coming back from an injury and might be selected for low-leverage work as he gets back into his normal pitching routine. 

From this you can see that Brian Price turns to Sam LeCure when the Reds need to buckle down a win, followed by Broxton and Manny Parra (who, with a 3.84 xFIP, appears to have pitched better than his line this year). Logan Ondrusek and J.J. Hoover round out the pitchers who enter a game when the Reds are in tight situations.

Two pitchers on the list, J.J. Hoover and Trevor Bell, have the inglorious designation of leaving the game in worse shape than they entered it, on average, a rather amazing feat. [I will reiterate small sample size bias here: J.J.’s numbers are not helped by giving up a grand slam walk-off home run. His work this week will help his numbers.].

The good news is that the Reds will be able to bump Ondrusek and Hoover down into low leverage situations once Chapman and Simon return to the bullpen. This index might also give us some insight into who Price will designate for Louisville once the Reds bullpen is back to full strength. As the season progresses we will keep an eye on the leverage index to see who our new skipper turns to when the Reds need help.