CHICAGO -- Neil Walker remained out of the lineup on Sunday, one day after being forced off Wrigley Field by soreness in his right side.
"That's all we can call it now, until it calms down and they can re-evaluate it," said Walker, who anticipates undergoing an MRI on Monday in Pittsburgh.
Walker held an ice pack to his right side and was also being given medication for what he said began as a "cramping feeling" early in Saturday's game against the Cubs. He went 0-for-2 and made one play in the field -- turning a line drive into a double play -- before leaving in the bottom of the fifth.
"I just felt something. I didn't know what it was, but I wanted to be careful," he said. "I've talked to a couple of the other guys who've had something similar, and they said you just have to give it a couple of days to calm down and go from there. I don't expect it to be anything extended."
"He's day to day and will be re-evaluated by our doctors," manager Clint Hurdle said.
The veteran Brandon Inge started Sunday's game at second base, and made a fine defensive play for the final out of the first inning.
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. This story was not subject to the approval of Major League Baseball or its clubs.