Nationals manager Davey Johnson says third baseman Ryan Zimmerman eventually could change positions if his throwing problems don't get sorted out.
Johnson adds Tuesday he thinks Zimmerman's issues are ''more mental'' than physical.
Zimmerman had offseason surgery on his right shoulder.
He has made 17 errors this year; among major league third baseman, only Pittsburgh's Pedro Alvarez has made more, 20. Zimmerman's .934 fielding percentage ranks 23rd at third base.
Asked whether Zimmerman's shoulder might lead to him playing elsewhere in the field, Johnson said: ''If that doesn't get better, then obviously it's not a good spot for him to be in.''
Fiddling with his slumping lineup, Johnson batted Zimmerman second Tuesday, the only time in his nine-year career he's started a game hitting in that spot.