Ramirez has not started since April 24 because of a strained left calf.
"It's in a tough spot," Ramirez said Sunday. "You've got to use your calf for everything, but I'm a lot better today and feel pretty good now."
There is some discomfort, but Ramirez said he'll just have to play through it.
"There's going to be pain, but I guarantee you at least 90 percent of the guys are playing through pain now," Ramirez said. "We'll see how I feel after [Sunday]. I feel pretty good where I'm at now."
Piniella said Ramirez was "almost sure" for Monday's night game against the San Francisco Giants. However, when he does return, the Cubs may not go with the projected 3-4-5 lineup of Derrek Lee-Milton Bradley-Ramirez. Kosuke Fukudome has done well in the No. 3 spot and may stay there in the lineup.
"I think we're going to change the combination a little bit when we do get [everybody] back," Piniella said, refusing to tip his hand. "It'll be nice to get everybody in the lineup and playing."
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.