The Texas Rangers, meanwhile, keep finding ways to win on their longest road swing of the season.
Strasburg will try to help Washington avoid its seventh loss in eight games Friday night and deny the Rangers their eighth win in 10 contests as they open a three-game set at Nationals Park.
Washington plated five runs for only the second time in that span Wednesday while finishing with 15 hits for the first time since Harper last played April 25, but still lost 8-5 in 10 innings to visiting Miami.
The short-handed Nationals also have struggled in Strasburg's five May starts, totaling just nine runs of support. He finished with seven strikeouts over seven innings Saturday, but gave up two of his three runs in the seventh in a 3-2 loss at Pittsburgh.
"It's tough - we're all trying very hard, trying to get back on track," the right-hander said. "I do think we've probably reached the point where we're trying too hard and need to take a step back and let the game come to us."
Since going 1-2 with a 6.00 ERA in his first four outings, Strasburg (3-4, 3.42 ERA) has gone 2-2 with a 2.28 ERA over a string of seven consecutive quality starts. He also ranks among the major league leaders with 81 strikeouts.
The 2012 All-Star is 2-1 with a 1.80 ERA in four career interleague home starts.
Texas (28-26) totaled 42 runs with a .349 average to win four of the first five on a season-high 11-game trip before its injury-depleted pitching staff led the way with a 2.36 ERA while taking two of the last three.
"Those guys have had to grind, and everybody has had to have been used," manager Ron Washington said. "So that's the way you play team baseball, and that's exactly what we're doing."
Adrian Beltre was one of four players with two hits Thursday as the Rangers won three of four in Minnesota with a 5-4 victory. Beltre has a .395 average over his last 11 games, while Leonys Martin has gone 4 for 7 with three doubles in his last two.
Alex Rios also has been on a tear, batting .404 during a 12-game hitting streak. He has a .429 average with 10 RBIs over his last nine games versus Washington dating to his time with Toronto.
Texas starter Colby Lewis (4-3, 5.10) looks to remain undefeated on the road after allowing two runs while overcoming five walks in 5 2-3 innings to earn the win in a 12-4 victory at Detroit on Sunday.
Lewis, 3-0 with a 2.86 ERA in four road starts, has gone 5-1 with a 2.00 ERA in six interleague road outings since his second stint with the Rangers began in 2010.
Closer Joakim Soria could be unavailable after pitching in the last three games.
The Rangers are 4-5 all-time against the Nationals, but they took two of three in D.C. in June 2008.