WASHINGTON -- When the Washington Nationals signed Nate McLouth prior to this season, they envisioned a fourth outfielder who could provide both power and speed when needed.

But a disappointing season is over for McLouth, who spent the past two years with the Baltimore Orioles.

McClouth has been on the disabled list since Aug. 4, retroactive to Aug. 2, and he will have surgery on Thursday and will be done for the year, according to manager Matt Williams. "He has a torn labrum," Williams said Tuesday.

Williams said McLouth hasn't been the same since he dove for a ball in Miami against the Marlins in late July. "That dive really hurt him. It hasn't gotten better. That is the time frame when it got a lot worse," Williams said.

McLouth hit .258 with 12 homers last year for the Orioles. He was an All-Star in 2008 with the Pittsburgh Pirates and he has also played for the Atlanta Braves.

He entered this season with an average of .250 with 56 homers. This year, he is hitting .173 in 139 at-bats.

McLouth should be ready for spring training, according to Williams. "Get it fixed and be ready for next spring," Williams said.

On Monday, the Nationals signed veteran outfielder Nate Schierholtz to a minor league contract. He had 19 extra-base hits in 99 games earlier this season with the Chicago Cubs.

Right now, whatever general manager Mike Rizzo does seems to be working, as the Nationals won their eighth game in a row on Tuesday with an 8-1 win over the Arizona Diamondbacks as shortstop Ian Desmond had three hits and four RBIs and Stephen Strasburg allowed just one run in eight innings and lowered his ERA to 3.41.

"They have put together a streak where they have played well," said Williams.