The Nationals announced that they designated right-hander Collin Balester for assignment to create roster space for left-hander Ross Detwiler. The move is a formality because Balester has more than three years of service time, according to Adam Kilgore of the Washington Post (Twitter links). Though the move technically vacates a spot on Washington's 40-man roster, Balester will be back on the roster later this week.
Balester, 25, has a 4.61 ERA with an 11K/8BB ratio in 13 2/3 innings this season. In parts of four years with the Nationals, he has a 5.28 ERA with 6.8 K/9, 3.8 BB/9 and a 41% ground ball rate.