Alex Avila and Torii Hunter hit homers in a five-run second inning and Detroit scored five more runs in the fourth inning, getting a relatively strong outing from Justin Verlander after his shaky start.
The AL Central-leading Tigers took the two-game series, have won five straight and nine of 10. Detroit's superstar, though, is ailing again and its All-Star shortstop faces a possible suspension.
"I feel better," Cabrera said after missing the game with a strained lower abdomen. "Hopefully, we can get out of way this quick and try to be 100 percent Friday."
After a day off Thursday, the Tigers open a series against the Chicago White Sox and might not have Peralta in the lineup. He doubled in a game that might be his last until late September because he's among the players linked to the Biogenesis case.
Peralta said he shouldn't be on the dubious list.
"It's wrong," he said. "But whatever happens, I need to fight and try to move on."
Before and after the game, Peralta insisted he did not know whether Major League Baseball planned to suspend him.
"I don't feel nervous," he said. "But yeah, I worry a little bit because I want to play every day here, and I love to be here in Detroit."
If Peralta is suspended 50 games for first offense under baseball's drug program, he would lose $1,639,344 of his $6 million salary. Barring rescheduled games, he would not be eligible to play until Sept. 24, leaving him with just five games of the regular season. He would be eligible Sept. 14 for an injury rehab assignment -- if any of Detroit's minor league teams remain in their playoffs.
Peralta is batting .307 with 10 homers, 53 RBIs and a team-high 29 RBIs in 101 of the team's 106 games.
"He's very important to this team," Verlander said. "He's obviously had an All-Star-caliber season, and he's gone out there and played just about every game at shortstop.
"You lose a guy like that, that's tough. But I can't comment on how it would go to lose him because I don't know what the possibilities are."
Tigers general manager Dave Dombrowski said the team protected itself against a possible suspension by acquiring slick-fielding infielder Jose Iglesias from Boston in a three-team trade Tuesday night.
"If it were a 15-day thing, like a typical injury, I think we could have comfortably dealt with it with the players we already have," Dombrowski said. "But when you start to talk about 50 days and a possible playoff run, we feel better going ahead with Jose."
Verlander (11-8) shook off a rough start by giving up only one run, four hits and a season-high matching five walks while striking out six over six innings.
"My stuff was pretty good, but I was obviously erratic," he said.
Gio Gonzalez (7-4) gave up 10 runs -- one short of his career high -- and 11 hits -- the most of his career -- over 3 1/3 innings. He entered the game with 4-0 record and a 2.06 ERA in his 10 starts, in which he allowed three or fewer runs, since his last loss on May 27.
"In three months, you're going to run into a hiccup," Gonzalez said. "It just happened to be against a good team."
Nationals manager Davey Johnson said Bryce Harper didn't finish the game because of a hip spasm.
"I think he's going to be all right," Johnson said.
Harper, though, was fuming about the fortunes of the Nationals, who have lost nine of 13 games since the All-Star break to create a double-digit deficit behind the NL East-leading Atlanta Braves.
"You got to play with heart," Harper said. "You got to play as a family. Everybody's got to want it, starting with the manager on down -- everybody. Everybody wants to win this and keep going. We need to get going and play better, hit better, have better ABs in certain situations and pitch better also. It's just something we need to do.
"We play the Braves nine games. This ain't over. I really don't think it's over. We just got to keep going, keep grinding and turn into the family that we were last year."
Nationals pitching coach Steve McCatty, a Detroit native, has been released from a hospital after being treated for an irregular heartbeat and high blood pressure and is expected to rejoin the team Monday. ... Hunter was 4-for-5 with two doubles, two runs and three RBIs. ... Nationals OF Jayson Werth had a sacrifice fly in the first, driving in the only run for his team.