Here are the numbers for two pitchers. One of these pitchers is seen as a potential mid-season upgrade for the Pirates, and a guy who could help them for a playoff run. The other pitcher is a guy who is currently in the Pirates' rotation, and who a lot of fans would have as the top candidate to be moved to the bullpen or traded away.
Player A: 3.92 ERA / 4.04 xFIP
Player B: 4.07 ERA / 4.23 xFIP
You can tell by the title that one of these is going to be A.J. Burnett. He's actually Player A. The other player? Edinson Volquez. And the difference between the two? If Volquez had two fewer earned runs, he'd have a better ERA this season than Burnett. The advanced metrics show that the two aren't far off with their performances this year.
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.