Washington has won three straight games and six of eight overall since general manager Mike Rizzo expressed his faith in the team as constituted at the trade deadline.
The teams will play a split doubleheader Saturday afternoon and evening. The Nationals also have a doubleheader on Tuesday against the Atlanta Braves, giving them two twinbills in four days with an off day on Monday.
Friday's scheduled starters, Washington left-hander Gio Gonzalez (6-7, 3.78 ERA) and Cincinnati right-hander Anthony DeSclafani (4-3, 5.47), will pitch the day game.
Gonzalez hasn't won since May 28 but turned in a solid effort his last time out against the Miami Marlins, when he allowed a run and three hits in seven innings but getting a no-decision in a 2-1 loss.
"It's definitely moving forward, it's definitely good progress," Gonzalez told MLB.com. "Still working on little things, but it's progress, definitely something positive."
Gonzalez is 5-2 with a 2.47 ERA in 10 career starts against the Reds. In his only start against Cincinnati this season, Gonzalez gave up one run and five hits over six innings and picked up the win in Washington's 6-5 victory on April 1.
DeSclafani allowed three runs and five hits in 4 1/3 innings of a no-decision against the Philadelphia Phillies last Friday. He struck out seven and walked two but was lifted after throwing 87 pitches and allowing two one-out hits in the fifth inning.
DeSclafani is 1-0 with a 2.45 ERA in six career games (three starts) against Washington. He has not faced the Nationals this season.
Right-hander Matt Harvey (5-6, 5.13) makes his 15th start for the Reds in the second game.
Harvey allowed eight runs and eight hits, including four home runs, in 3 2/3 innings on July 22 but bounced back last Saturday, allowing two runs and two hit in five innings of a no-decision against the Phillies.
The Reds retained Harvey at the trade deadline, apparently not persuaded by any of the offers they received, A free agent at the end of the season, Harvey could clear waivers and be dealt before Aug. 31.
"I talked to my agent (Scott Boras) and they expressed how much they like me here," Harvey told the Cincinnati Enquirer. "It's nice to be wanted. They wanted to have me here. I really appreciate that. They gave me an opportunity by (trading for) me from the Mets. I've really enjoyed every minute of it."
Harvey is 3-6 with a 3.38 ERA in 16 games (15 starts) against the Nationals in his career. This season, he had one start against the Nationals while with the Mets, giving up nine hits and four runs in the Nationals' 6-5 victory on April 8. Harvey did not get a decision in that game.
Jeremy Hellickson (4-2, 3.59) goes for the Nationals in the night game.
Hellickson allowed five runs (three earned) in 4 2/3 innings of a 5-0 loss in Miami last Sunday. He was plagued by two-out hits and left after throwing 81 pitches.
"Just got to bear down with two outs and get that last guy," Hellickson told the Washington Post. "It's happened too many games in a row now."
Hellickson is 2-1 with a 1.50 ERA in four career games against the Reds. He has struck out 25 batters and walked just three in those starts. This will be his first start against the Reds this season.
The Washington offense is heating up.
Bryce Harper is hitting .359 (14-for-39) with three homers and 13 RBIs since the All-Star break and Daniel Murphy is 24-for-59 (.407) in his last 19 games. Meanwhile, Anthony Rendon continues to produce. He has his safely in 32 of his last 37 games (.325).