The Cubs are expected to sign John Grabow to a two-year deal worth about $7.5 million today. If you want to learn why this is a poor move by the Cubs, check out Dave Cameron’s article over at FanGraphs. Personally, I thought this might be a good time to point out how much we tend to overrate the value of relievers.
Many Pirate fans probably think of Grabow as a reliable reliever. My personal opinion is that he is an average-ish guy out of the pen. Over the last seven seasons, he has made 420 appearances and thrown 388.1 innings for the Pirates and Cubs. Over that time he has been worth somewhere between one and two extra wins. If you prefer to go by Win Probability Added to include Leverage in the equation, he has been worth closer to five wins. Andy LaRoche’s uninspiring 2009 season was worth about 2.5 wins on its own.
Individual relievers simply are not that valuable. The best relievers in the game are generally worth about three or four wins per season. Average relievers are worth more like half a win. Bullpens as a whole are more important. The difference between the best and worst bullpens is probably around 10 wins over the course of a season. But individual relievers, outside of the dominant ones like Mariano Rivera, simply do not have a large effect on a team’s record.
Remember that if you ever find yourself upset when we lose someone like Jesse Chavez in a trade.