The Nationals will turn to right-hander Jeremy Hellickson (2-0, 2.30 ERA). He will be matched against Braves right-hander Anibal Sanchez (1-0, 3.00), who is making his second start since coming off the disabled list.
Atlanta won the first two games of the series between the National League East frontrunners, but Washington won the four-hour marathon Saturday and pulled to within a half game of the Braves.
Both teams used six relief pitchers Saturday.
Atlanta used Sam Freeman, Shane Carle, A.J. Minter, Peter Moylan, Jesse Biddle and Miguel Socolovich. Biddle struck out eight batters in his three-inning stint, but Socolovich gave up two runs in the 14th, including a pinch hit to pitcher Max Scherzer.
"Those guys did a great job of getting us in the dugout and giving us a chance to win," Atlanta manager Brian Snitker said.
Snitker did not use closer Arodys Vizcaino or setup man Dan Winkler in the 14th, opting to give them another day of rest. The Braves could add left-hander Luiz Gohara to the active roster. He returned from a bereavement visit with his ailing month in Brazil and could provide long relief if needed.
Madson, activated from the disabled list on May 30, gives the team an added dimension in late-inning situations, but manager David Martinez said he will not overuse the right-hander, who has thrown in the last two games.
"We've got to be real careful," Martinez said. "Here's a guy who wants to pitch. Every time he's available, he wants to go out there. I have to be a little smarter with him and tell him, hey, I know you feel like you're available, but let's kind of give you that extra day."
Hellickson, who made the rotation after being signed as a minor league free agent in March, has been a consistent force all season. He has made eight starts and has not allowed more than three runs in any outing. In seven of those starts, he has allowed two or fewer runs and two times he has posted a scoreless effort.
Hellickson's issue has been the inability to go deep into a game. Only once has he failed to pitch five innings, but only once has he pitched into the seventh inning. Hellickson took a perfect game into the seventh that day against the Padres.
Hellickson has not faced the Braves this season. In five career starts against Atlanta, Hellickson is 2-0 with a 3.21 ERA. He has struck out 20 in 28 innings, with only two home runs.
Sanchez received a no-decision in his last start May 29 against the New York Mets. He gave up four runs in four innings and allowed two home runs in a game the Braves eventually came back to win.
Sanchez had been out six weeks with a right hamstring strain suffered while running in the outfield between starts. He has faced the Nationals once this season, a three-inning scoreless relief stint April 2 that saw him allow one hit. He has enjoyed tremendous success during his career against Washington, going 9-1 with a 2.11 ERA in 23 appearances (22 starts).