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8/4/2014 1:51 P.M. ET

Harper sits against Hamels; Hairston makes rare start

WASHINGTON -- Although left fielder Bryce Harper is hitting .302 against left-handers this season, Nationals manager Matt Williams decided to sit the lefty slugger Sunday and start Scott Hairston against Phillies left-hander Cole Hamels.

Hairston has been successful against Hamels, going 16-for-41 (.390) with five home runs and nine RBIs against him entering Sunday. In Washington's 4-0 victory against Philadelphia, Hairston went 1-for-3 against Hamels. 

"I've been able to pick the ball up early against him off his release point," Hairston said before the game. "It's not a thing where it's an easy at-bat. He has been pitching for a long time. Whenever I hit the ball against him, it always finds a hole."

Hairston has had an up and down season off the bench. After starting 9-for-20 (.450), Hairston entered Sunday in a 3-for-30 (.100) slump.

"There have been ups and downs," Hairston said. "There are four or five days where I don't get an at-bat. I feel good one day, the next day, it feels I haven't swung a bat in weeks. For the most part, it has to do with timing. My season so far, it could be better. I'm doing the best I can with the situation I'm in."

Hairston learned how to come off the bench from his father, Jerry Hairston Sr., who was a pinch-hitter extraordinaire mostly with the White Sox in the 1970s and 80's.

The elder Hairston taught his son to keep himself in shape throughout the game, like riding the exercise bike for a couple of minutes, stay ready and pay attention on how the game is unfolding.

"That has helped me as time goes by as long as I'm in this role," Scott said. "You might pinch-hit in the fourth inning. You never know."

McLouth goes on DL, prospect Souza called up

WASHINGTON -- The Nationals called up outfielder Steven Souza Jr. on Monday and placed outfielder Nate McLouth on the 15-day disabled list because of inflammation in his right shoulder.

Souza, 25, is having a tremendous season, hitting .354 with 18 home runs and 72 RBIs for Triple-A Syracuse. The Chiefs were playing Scranton/Wilkes-Barre on Sunday when Souza was taken out in the first inning.

Souza -- Washington's No. 5 prospect -- more than likely will come off the bench and may get an occasional start. McLouth injured his shoulder making a diving play in a 7-6 loss to the Marlins on July 28.

McLouth, who signed a two-year deal in the offseason, is hitting .173 with one home run and seven RBIs.

Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the Time. He also can be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.