PITTSBURGH — The Pittsburgh Pirates have made a number of changes to their bullpen this season, with their most recent one impacting their 40-man roster. The Pirates announced that they designated right-handed relief pitcher Ryan Harbin for assignment, as they selected the contract of right-handed relief pitcher Chris Devenski . Devenski had signed a minor league contract, but with the Pirates calling him up, they had to create spots on both the 26-man roster and the 40-man roster, which sees them place Harbin on waivers. It's a decision that likely didn't come easily for the Pirates, as they will want to see their young reliever get a chance to prove himself again this season. Why the Pirates DFA'd Ryan Harbin The Pirates added Harbin to the 40-man roster back on Nov. 6, as they looked to protect him from the Rule 5 Draft, which would've allowed other teams to put Harbin on their 40-man roster for the next season.…