Prior had impressively racked up 38 strikeouts in 25 innings as a reliever for Pawtucket, holding opponents to a .172 batting average. So why would the Red Sox release him from Triple-A? Because he couldn’t throw the ball over the plate, walking 23 batters in those 25 frames.
That includes a 15/13 K/BB ratio in 15 innings over his last 10 appearances, during which time Prior coughed up seven runs.
Obviously with nearly 14 strikeouts per nine innings and a sub-.200 batting average against there’s still some juice left in Prior’s oft-injured arm and he’s still only 31 years old, but he hasn’t pitched in the majors since 2006 and clearly wasn’t going to get an opportunity with the Red Sox.