All the graphs are pulled from this Fangraphs leaderboard.
The Pirates bullpen has a been a source of problems and criticisms for the Pirates this year. At the beginning of 2014, the bullpen had almost the same personnel as the 2013 season. Bullpens can vary wildly from year to year, and the Pirates relievers pitched out of their minds for most of 2013, so you’d expect there to be some fall off. Currently [August 26, 2014], the Pirates lead MLB with 22 blown saves. Personally, I abhor saves and blown saves, but I needed to get this out of the way, since it’s the stat that will get thrown around the most. And for reference Tony Watson [the All-Star] leads the team with 6 blown saves. So there’s that.
I wanted to look at some of the peripheral stats of the Pirates bullpen to understand the entire story. First, the Pirates starters have been terrible this year. They rank last in starter WAR, middle of the pack in FIP, and near the bottom in WPA. Analyzing that situation is for another day, but suffice it to say they give up a lot of runs before the bullpen gets into the game. The smaller the average lead the bullpen has to hold on to, the more often they will give up the lead [accrue a blown save]. Shutdowns and meltdowns are Fangraphs stats which are better for evaluating individual relievers than saves. They provide a broader evaluation of how a pitcher or bullpen has performed rather than just looking at save situations. For a shutdown a pitcher basically adds to the win probability while for a meltdown a pitcher subtracts from the win probability. For instance last night Jared Hughes had a meltdown allowing three runs and inverting the win probability.
The Pirates are in the middle of the pack for both of those stats. There really isn’t anything interesting here.
Finally, the Pirates’ reliever xFIP is not very good. It’s towards the lower end of MLB. xFIP is one of the better park-independent, context-independent predictors of pitching skill. It just uses BB, K, and flyballs [for HR/FB]. This will also ‘adjust’ for some of Grilli and Frieri’s HRs that they gave up when they were struggling earlier this year. Those struggles won’t affect the bullpen moving forward since they are no longer on the team.
After this quick analysis to answer my initial question about the Pirates bullpen, they aren’t good. They aren’t terrible, but they aren’t good. They do have two really good pitchers with Melancon and Watson. Two decent pitchers in Wilson and Hughes. Then the rest aren’t great. Taking this analysis, what could the Pirates do to improve? Frieri was a gamble that didn’t pay off. But honestly, I think from a management stand point, you had to get rid of Grilli to get him out of the closer role. John Axford might help. He’s been good in the 5 appearances for the Pirates so far, and his career xFIP is 3.26 which is pretty good. As far as a trade, ‘proven’ relievers are overvalued in the free agent market, and the trade market was really expensive this year. Overall, one reliever isn’t going to affect your win total dramatically.