The 33-year-old McGowan has already been outrighted off the 40-man roster once this season but remained with the organization after he cleared waivers. He’ll have the option o elect free agency once again, if he is ultimately exposed to waivers and clears for a second time. The veteran swingman has struggled with his control this season, leading to a 6.94 ERA in 23 1/3 innings. McGowan’s 21 strikeouts in that time are a solid mark, but he’s also walked 20 hitters, and his ground-ball rate is down significantly from its peak — a trend that began last year in Toronto and has continued in 2015.
Diekman, 28, entered the season as one of the more intriguing arms in the Phillies’ bullpen mix but struggled to a 6.75 ERA through 21 1/3 innings before being optioned to Triple-A earlier this month. His brief trip to the minors was as encouraging as Phillies’ decision-makers could possibly have hoped, as he fired seven scoreless innings, allowing just five hits and a walk while punching out seven batters. Diekman whiffed 100 hitters in just 71 innings last year and posted FIP, xFIP and SIERA marks between 2.64 and 2.85, suggesting that he had performed much better than his 3.80 ERA otherwise indicated. He’ll likely rejoin Ken Giles as a setup option for closer Jonathan Papelbon, though he could move into a more prominent role in the Philly bullpen if Papelbon is ultimately traded.