The Nationals selected Edwards' contract from Triple-A Rochester on Tuesday.
Edwards received a well-deserved call-up to the big leagues after he struck out 17 hitters and issued four walks over 14.1 innings at Rochester while submitting an 0.63 ERA and 0.50 WHIP. The 30-year-old has seven prior years of MLB experience, but he's seen sporadic work in the big leagues in each of the last three seasons while turning in a 7.90 ERA over that stretch.