Bryce Harper likely will not play again this season, Nationals manager Davey Johnson said Friday.
Harper, the Nationals' top prospect, was carried off the field on Thursday night in Akron after suffering a strained right hamstring while running from first to third base.
"He probably won't play the rest of the year, as far as I know," Johnson told MASN. "There's only a few days left. You take a chance of aggravating it and it becomes more of a serious injury."
Harper reportedly was headed to Double-A Harrisburg's seven-day disabled list regardless. According to the Washington Post, Harper was evaluated by members of the Nationals training staff on Friday in Harrisburg, although the results were not immediately available.
"I'm not going to worry a whole lot about Bryce Harper down there with a slightly pulled hammy," Johnson told the newspaper. "It's the end of the season."
Harper would miss the remaining 18 regular-season games, although the Senators are in first place in the Eastern League's Western Division and could reach the playoffs.
The Nationals had planned to send Harper back to the Arizona Fall League, a move that still could happen, depending on the severity of the injury. The No. 1 overall pick in the 2010 Draft batted .343 with a homer and seven RBIs in nine games last fall with the Scottsdale Scorpions.
Still only 18 years old, Harper is hitting .297 with 17 homers, 58 RBIs, 26 stolen bases and a .392 on-base percentage in 109 games across two Minor League levels. He was a South Atlantic League All-Star with Class A Hagerstown but has cooled off since a promotion to Double-A, batting .256 with three homers, 12 RBIs and seven steals in 37 games.
The Las Vegas native played for the U.S. team last month in the All-Star Futures Game in Phoenix.
Harper ranks fourth among Nationals farmhands in homers, fifth in OBP and fourth with a .501 slugging percentage.