"It's going to take a few days, two weeks, whatever to get the back straight," Uggla said. "It locks up on you. There is nothing you can do about it. I'll get some treatment on it, have [the trainers] work on me. I hope to be back soon."
Uggla is hitting .191 with a home run and 14 RBIs in 56 games this season.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the Time. He also can be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.