BALTIMORE -- It's official. Chris Tillman is headed to the DL.

OK, so maybe it's not really official yet. But Baltimore Orioles manager Buck Showalter said after Tuesday night's 8-1 win over the Washington Nationals that his ace is headed to the 15-day disabled list with shoulder inflammation. So let's call it unofficially official. Which unofficially officially makes the Orioles' chances of reaching the playoffs a whole lot worse than they would've been if Tillman were healthy.

Entering Tuesday's action, the Orioles were in third place in the AL East, two games behind Boston and Toronto, and one game ahead of Seattle for the second AL wild-card spot. According to projections by FanGraphs, they had a 44 percent chance of making the postseason. Baseball Prospectus gave them a 32 percent chance of making the playoffs. With Tillman out, those odds are sure to get longer.

With a rotation that has been flimsier than a paper airplane in the Bermuda triangle during hurricane season, Tillman has been the undisputed anchor. When he starts, the Orioles have a .770 winning percentage (20-6). When anyone else starts, the O's are sub-.500 (49-50).

Aside from Tillman, whose 15 wins are tied for second in the American League, Baltimore doesn't have a single starter with more than five W's. In other words, with Tillman and his bum shoulder on the shelf, the Birds are up the creek without a paddle ... or a boat. At least, that's the prevailing logic in and around Charm City. But if their latest win over Washington is any indication, the Orioles have other plans.

In order for the O's to stay afloat sans Tillman, regardless of how long he's out, they'll need to get contributions from everyone. That's exactly what happened on Tuesday against a Nats squad that came in with the second-best record in baseball.

Every player in Baltimore's starting lineup reached base via hit or walk. Five different hitters drove in runs, and six different guys scored. Starter Kevin Gausman went six scoreless. Vance Worley worked three innings to get his first career save. Catcher Matt Wieters gunned down Trea Turner trying to steal twice, which is one more time than the rookie speedster had been caught previously this season. Even Showalter got into the act, going 3-for-3 in replay challenges.

"It certainly helped," said Showalter, who became the third manager this season to win three challenges in the same game. Two of his successful challenges came on Turner's steal attempts, both of which were initially ruled safe. "We needed each one of them. It kept any momentum from getting going."

If the O's are going to keep their own momentum going without Tillman, they'll need to continue the all-hands-on-deck approach, both when the Battle of the Beltway relocates to Nats Park on Wednesday, and beyond.

"We are going to miss him on the mound," center fielder Adam Jones (4-for-5 on Tuesday) said of Tillman, "but we're still going to keep fighting and grinding. When he comes back hopefully after the 15 days, mid-September, whenever he does, he comes back fresh and ready to make his last three or four starts in a tight race."

For what it's worth, Tillman himself doesn't seem terribly concerned about how his team will fare without him. Or, if he is, he's not letting it show.

"These guys are hitting the ball well, having fun as a group," Tillman said. "So we'd like to keep it going. We're playing good baseball."

Only time will tell if it's good enough.