There are two things I feel should be common knowledge by now about relief pitchers.
1. Relief pitchers are very volatile.
2. ERA is a horrible stat to evaluate relievers.
The Pittsburgh Pirates have had success finding strong relievers at low costs because they've ignored short-term struggles, and have looked past a poor ERA to see potential with advanced metrics. Meanwhile, other teams give out long-term deals to relievers, paying them millions of dollars, and mostly for the ERA.
Eventually other teams are going to get it, but it doesn't look like that has happened yet.
The trade between the Angels and the Pirates looks like the Mark Melancon trade all over again. The Pirates sent Jason Grilli for Ernesto Frieri. They dealt an aging reliever who looks like he's on a rapid decline, for a 28-year-old reliever who throws 94 MPH, has put up solid numbers in the past, has an inflated ERA, but has advanced metrics that say he should be better, and a glaring HR/FB ratio that ...
Tim is the owner and editor in chief of Pirates Prospects. He started the site in January 2009, and turned it into his full time job during the 2011 season. Prior to starting Pirates Prospects, Tim worked with AccuScore.com, providing MLB, NHL, and NFL coverage to various national media outlets, including ESPN Insider, USA Today, Yahoo Sports, and the Wall Street Journal. He also writes the annual Prospect Guide, which is sold through the site. Tim lives in Bradenton, where he provides live coverage all year of Spring Training, mini camp, instructs, the Bradenton Marauders, and the GCL Pirates.