Who closes for the Orioles today?

If the Orioles take a slim lead into the bottom of the ninth inning today at Nationals Park, I'd bet that Darren O'Day would be used as the closer. Not because manager Buck Showalter is ready to assign Jim Johnson's duties to another reliever. I still don't believe that he's reached that point. But Johnson threw 37 pitches yesterday and 51 over the past two games. He's probably not available today. Tommy Hunter's right hand was swollen yesterday after fielding Jose Bautista's hard one-hopper in the eighth inning. X-rays were negative, but he's supposed to undergo another one today. Eliminate him from consideration. It's got to be O'Day, who wasn't available yesterday after pitching three of the last four days. O'Day is 2-0 with a 1.96 ERA in 24 games, but he's allowed at least one hit in 10 of his last 13 appearances. In one of the hitless outings, he walked two batters in two-thirds of an inning. He's surrendered 18 hits, walked nine, struck out 25 and hit five batters in 23 innings. He hasn't dominated, but he's only allowed six runs (five earned) this season. Johnson gave up four yesterday. O'Day hasn't surrendered a run or hit to the Nats in three career appearances over four innings. Fans are asking whether Johnson is hurt. If so, it's been kept quiet. Showalter repeated yesterday on "O's Xtra" on MASN2 that Johnson is fine physically. He also indicated that he'd give Johnson the ball again in a save situation. Jason Hammel is 5-0 with a 3.30 ERA in seven games against the Nats, with nine walks and 37 strikeouts in 46 1/3 innings. He's 3-0 with a 3.51 ERA in four games at Nats Park. Ryan Zimmerman is 7-for-21 with a double and home run against Hammel. Bryce Harper is 0-for-7, but he could miss the series because of a knee injury. He's considered day-to-day. Nats left-hander Gio Gonzalez is 1-2 with a 3.26 ERA in five starts against the Orioles. Matt Wieters, who had four hits and three RBIs yesterday, is 7-for-13 with a double and home run against Gonzalez. Danny Valencia is 3-for-8 with a double. J.J. Hardy's been swinging a hot bat, but he left eight runners on base yesterday while the Blue Jays kept walking Chris Davis. Valencia stranded five.