Choo is hitting .244 on the season, but is batting .152 with 11 strikeouts in the past eight games.
In the first three games of the four-game series against the Angels, Choo was 1-for-12 with six strikeouts. Washington hopes his left fielder will be ready to go at the end of the All-Star break and when the Rangers head to Toronto.
"Just got to get himself back mentally," Washington said. "Hopefully these days will rejuvenate him."
Grace Raynor is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.