BALTIMORE (AP) Just when it appeared as if the Baltimore Orioles had righted themselves, bad news arrived in the form of an unfavorable medical report.
Soon after the Orioles beat the Washington Nationals 8-1 on Tuesday night, manager Buck Showalter confirmed that ace Chris Tillman is likely to be sidelined with a sore right shoulder.
''I think he's going to be on the disabled list,'' Showalter said. ''They were talking about whether or not they were going to inject him. ... I think that would be a sign of where he is heading.''
Tillman is 15-5. No other starter on the team has more than seven wins.
''We're trying to be safe, get this thing in the rear-view mirror,'' Tillman said. ''That way I'm not fighting it all year.''
If the Orioles are to stay in contention for the AL East title or a wild-card berth, they're going to need more pitching performances like the one they got from Kevin Gausman, who scattered six hits over six shutout innings.
Adam Jones went 4 for 5 and Chris Davis hit his 30th home run for the Orioles, who won two straight over Washington to conclude a 3-5 homestand.
''They're one of the best teams in baseball and in that league, so it was tough,'' Showalter said.
Baltimore is 34-24 against the Nationals in a rivalry that began in 2006. The series shifts 38 miles south to Nationals Park on Wednesday for the first of two games.
Gausman (5-10) walked two, struck out two and permitted only one runner past second base. He's 5-1 at home and 0-9 on the road.
''I've pitched well on the road. I just don't necessarily have the wins to show for it,'' the right-hander said.
The 25-year-old Gausman outpitched Nationals rookie Reynaldo Lopez, a 22-year-old making his fifth major league start. Lopez (2-2) yielded six runs, four earned, and seven hits in 2 2/3 rocky innings.
''The results were not what I expected,'' Lopez said through an interpreter. ''The game did not go the way I liked it to.''
Trea Turner had a career-high four hits for Washington. The Nationals trailed 6-0 after three innings and went quietly in their third straight loss - their longest skid since a seven-game run from June 18-25.
''It's good to be going home. It seems like we haven't been home in a while,'' Baker said following the conclusion of a nine-game road trip. ''We go home and regroup. Guys get to see their kids and their wives.''
Replay did the Nationals no favors. Turner was called safe on steal attempts in the first and third innings, but on both occasions the call was reversed after a replay review. Making the result more maddening for Washington: Jayson Werth followed with a walk both times.
The trend continued in the bottom of the third, when replay determined that Jones beat out an infield roller after initially being called out.
Mark Trumbo picked up his 93rd RBI with a first-inning single, and the Orioles made it 3-0 in the second when Matt Wieters doubled in a run and scored on a single by Jones.
In the third, Jonathan Schoop hit an RBI double and two runs scored when Daniel Murphy fumbled a two-out grounder to second base.
Washington got its lone run in the seventh inning when Danny Espinosa singled in a run off Vance Worley, who worked three innings for his first career save.
Davis connected in the eighth against Yusmeiro Petit. He has hit at least 30 home runs in four of the last five seasons.
Nationals: RHP Joe Ross (right shoulder inflammation) felt good after a bullpen session Tuesday. ''Our head trainer came in and gave me the thumbs up,'' Baker said. ''Hopefully, we're going to put him back to work here pretty soon.''
Orioles: With Tillman out, the Orioles announced that Ubaldo Jimenez will start in his place Thursday night in Washington.
Nationals: Tanner Roark (13-6, 2.87 ERA) starts Wednesday night. The right-hander is 4-0 in his last five starts and has lost just once since June 21.
Orioles: Wade Miley (7-10, 5.58) makes his fifth start with Baltimore. The lefty is 0-2 with a 9.53 ERA since being traded from Seattle.