Jenifer Langosch of MLB.com posted an article earlier today about how “The demands cast on the Cardinals’ bullpen over the past 10 days prompted the organization to promote reliever Victor Marte a day earlier than planned”.  She goes on to quote Manager Mike Matheny, who said that, “We need guys to help out the guys that have been carrying the load”, especially after a road trip where the bullpen averaged 3 2/3 an inning per game. This prompted two obvious questions: 1) How much more has the bullpen really been used over a longer period of time, say the past 10 games, and 2) How has the bullpen’s ERA been affected in that same period?

My research revealed that the bullpen has been averaging approximately 3 2/3 innings

Fresh Bullpen Arms

per game over the past 10 games, not only during this past road trip. This is a full inning above their season average of approximately 2 2/3 an inning per game. Considering that we’re nearing the end of a long season, the extra wear-and-tear of an inning per game is not insignificant. You would think that this increased usage might result in an accompanying rise in the bullpen’s ERA, due to tired arms, reduced velocity, etc. However, a simple calculation of the bullpen’s ERA over the past 10 games reveals that their ERA has actually been nearly half a run lower than their season average (~3.62 over the past 10 games vs. 4.02 for the season).

The Bottom Line: While the bullpen has been used approximately a full inning more per game over these last 10 games, it’s performance as reflected by it’s ERA has actually been markedly improve when compared to their ERA for the entire season. While the sample size of 10 games may be small, the influx of pitching arms that has arrived as part of the expanded 40-man rosters should help keep the bullpen’s  arms fresh for a deep playoff run.