WASHINGTON – Nationals Manager Davey Johnson thinks teenage prospect Bryce Harper probably will miss the rest of the minor league season.

Harper was evaluated by a doctor Friday after he was injured during Double-A Harrisburg’s 4-2 win at Akron on Thursday. The examination confirmed the 18-year-old slugger has a strained right hamstring, and he was placed on the seven-day disabled list.

“I’m not going to worry a whole lot about Bryce Harper getting hit with a slight pulled hammy,” Johnson said before Washington’s game against Philadelphia. “He probably won’t play the rest of the year, as far as I know. There’s only a few games left. No sense in taking a chance and aggravating it where it becomes more of a serious injury.”

Harrisburg’s regular season ends Sept. 5.

The No. 1 overall pick in the 2010 draft, Harper was hurt running to third base in the eighth inning Thursday and had to be helped off the field.

The Nationals have long said Harper would not play in the majors this season. He is hitting .256 with three home runs, 12 RBI and seven stolen bases in 37 games with Harrisburg. He previously batted .318 with 14 homers, 46 RBI and 19 stolen bases in 72 games this year with Class-A Hagerstown.

Harper’s next stop will be the Arizona Fall League.