The Nationals' No. 2 prospect suffered a badly sprained left ankle while running the bases for Class A Advanced Potomac on Saturday night. According to the Washington Post, the swelling must go down before the team will learn how long Rendon will be sidelined.

Rendon went down while rounding third base in the fourth inning of a 7-2 loss to the Lynchburg Hillcats. He had to be helped off the field by team staff.

After walking in his first at-bat, Rendon led off the fourth with a double to center field. Two batters later, Justin Bloxom lined a single to center and Rendon was trying to score when the injury occurred.

Winner of the Dick Howser Trophy as college baseball's top player during his sophomore season at Rice University, Rendon was considered the likely No. 1 overall pick in 2011 before a right shoulder injury interrupted his junior year. After hitting .394 with 26 homers in 2010, he batted .327 with only six longballs last season. He also was largely limited to designated hitter duty as a junior after playing stellar defense at third base the year before.

Rendon previously had issues with his right ankle. He tore ligaments in 2009, then suffered multiple fractures in the ankle and foot the following year.

The 21-year-old ended up going sixth overall to the Nationals in the 2011 Draft. In his pro debut on Friday, he went 1-for-3 with a triple, a walk and a run scored.