Updated at 5:41 p.m.
The Nationals are hopeful two days of rest and treatment will be enough to allow Zimmerman to return, though they won't know about his availability for this week's homestand until Tuesday.
This is the same injury that sidelined Zimmerman for three games early in spring training -- he also missed time late in camp with a separate groin strain -- and the third baseman has been experiencing some discomfort since Opening Day.
"When I slid into second last night, I hurt it a little more," Zimmerman said. "It's one of those things where we'll see how it feels. ... It feels bad enough not to play today. So worse than it was [during spring training], but it's not terrible. So we'll see."
Read more (including Adam LaRoche update)