Martin strained his lower back in his start against the Milwaukee Brewers on Saturday night. He lasted just 2 1-3 innings Saturday after aggravating a bulging disk in his back.
He will be placed on the 15-day disabled list to make room for left-hander Ross Detwiler.
"We're pretty much going to do everything we can to not have surgery," Martin said. "I know for a fact I don't need it right now."
He replaces right-hander Luis Atilano, who was placed on the 15-day disabled list Friday with bone chips in his right elbow.
Balester has not pitched for Washington this season after going 1-4 with a 6.82 ERA in seven starts last season.
Detwiler is expected to arrive from Double-A Harrisburg in time to start Sunday's game.
Detwiler, the team's No. 1 draft pick in 2007, will replace Atilano in the rotation. Detwiler has not pitched this season after undergoing surgery on his right hip last February.