Murphy, who was acquired from the Nationals on Aug. 21, had three hits, including a home run, as the Cubs beat the Brewers 6-4 to snap a two-game losing streak and increase their lead in the National League Central to four games.
Chicago is 11-5 in a stretch of 23 games in 23 days and manager Joe Maddon said he's proud of the way his team is handling it.
"I don't sense fatigue, the energy is good, pregame is good, talk in the dugout good," Maddon told mlb.com. "Normally at this time of the year, you feel more of that (fatigue). I think our ability to manipulate lineups and keep guys fresh helps. I think they know how to react."
Ironically, the other player Washington traded Aug. 21 -- Matt Adams -- homered twice Wednesday night to lead the Cardinals to a 7-6 win over the Nationals in the rubber game of that series. The Cardinals remain 4 1/2 games behind Chicago in the Central and are second in the wild-card race, two games ahead of the Los Angeles Dodgers for the final spot.
The Nationals continued the selloff they began Aug. 21 when they traded pitchers Gio Gonzalez and Ryan Madson last week. Meanwhile, the Braves and Phillies are slumping. Both have played sub-.500 baseball since Aug. 15, but so have the Nationals (9-10), failing to gain much ground.
Washington (69-71) dropped the final two games against St. Louis as late rallies fell short.
"We gotta finish some comebacks, we really do," Martinez said. They jump out to a 5-0 lead. Our guys don't quit. it's tough."
Martinez was speaking hours after general manager Mike Rizzo was asked during a session with reporters if his rookie manager -- formerly the Cubs bench coach -- would be back next season.
"I haven't considered any other scenario," Rizzo responded, later praising his manager's handling of the team.
Hendricks got a win last time out when he held the Phillies to a run on six hits in six innings Sept. 1. He was 3-1 with a 3.41 ERA in August and got a no-decision against Washington on Aug. 10, when he allowed two runs in six innings.
In his career, Hendricks is 2-2 with a 2.72 ERA in six starts versus Washington.
The Nationals have won all three of Strasburg's starts since he returned from a cervical nerve impingement. Last time out, he picked up the win against Milwaukee when he allowed two runs on five hits over six innings, with seven strikeouts and two walks. It was his best outing since his return.
"His velo's back plus the first few innings he was lights out," Martinez told mlb.com after the game. "That's the Strasburg that we've seen in the past. So hopefully he's got it now and he's good, and in five days we see that same Stras."
Strasburg is 1-1 with a 2.08 ERA in five regular-season starts versus the Cubs. In last year's divisional playoff series, he was 1-1 with a 0.00 ERA after allowing two unearned runs over 14 innings. He threw seven shutout innings to win Game 4 in Chicago.
Strasburg will try to stop the recent home run barrage against Washington pitchers, who have surrendered eight in the past two games.
"The home runs have really killed us," Martinez said. "I look back, and we're giving up way too many homers. We have to figure that out. We really do."