After sitting out five straight games with bursitis in his left knee, Washington Nationals outfielder Bryce Harper is “likely” headed to the disabled list on Saturday, a source with knowledge of the decision told The Washington Times.

The Nationals called up right-hander Erik Davis late Friday night and expect the reliever to join them before Saturday night’s game against the Atlanta Braves. Adding him to the 25-man roster will require a move, and it appears that putting Harper on the DL is it.

The Nationals had strongly hoped that they would be able to avoid putting their superstar 20-year-old on the DL, but the swelling and inflammation caused by the bursitis in his knee was not improving as quickly as they’d expected. The issue is believed to stem from Harper’s violent collision with the right field wall at Dodger Stadium on May 13.

Nationals manager Davey Johnson said Harper limped on to the team’s plane on Thursday night after hitting and running before their loss to the Orioles and the flight to Atlanta. But the hope was that they could allow him until the end of the weekend to see where his progress was.

With right fielder Jayson Werth possibly returning by Tuesday, the Nationals were looking to get their Opening Day outfield back together for the first time in a month.