Bradley is sidelined with a strained right groin, which forced him out of Sunday's game in Milwaukee. Monday's rain and wet grounds would create a risk of further injury for the outfielder. Piniella said he expected Bradley to be sidelined three to five days.
"He's gotten better," Piniella said of Bradley, who has one hit in 17 at-bats this season, a home run. "He's not going to play today, obviously, in this type of weather. I don't think it'll be very long before we get him out there playing."
Piniella wasn't exactly sure how Bradley got injured. He was hit by a pitch to lead off the fourth inning, advanced when Mike Fontenot walked, and ran gingerly to third on Ryan Theriot's single before being lifted for a pinch-runner.
"When he was at second base, he was exercising his leg a little bit," Piniella said. "I thought it was just tightness. I don't know exactly how it happened. I just talked to him before coming in here [to meet with the media], and he said he felt somewhat better than he did [Sunday]."
Ramirez showed up at Wrigley Field for the Cubs' home opener with a stiff back and was not in the lineup. The third baseman, who was batting .269 in six games, expected to be back on Wednesday. He was examined by the team doctors on Monday.
"[On Sunday], it was bad," Ramirez said. "[On Sunday] for some reason, I was really sore."
"In a 162-game schedule, you're going to have injuries and you're going to have things come up, and you need guys to step in and fill in and still be able to get wins," outfielder Reed Johnson said. "To say this team is going to be healthy, every single guy, 162 games, it's not going to happen. We have to have guys step up and not be intimidated by any situations, and I think we have a good group of guys, especially on the bench, who are willing to step up in those situations."
Catcher Geovany Soto, who has not played in nearly a week because of a sore right shoulder, was on track to start Wednesday in the second game of the Cubs' brief two-game series against the Colorado Rockies.
On Monday, Piniella moved Kosuke Fukudome from second to third in the lineup, dropped Derrek Lee to fourth and bumped Mike Fontenot up to fifth. Fontenot started at third, with Aaron Miles at second, Fukudome in right and Reed Johnson in center.
"We've got a different lineup out there today," Piniella said. "We've got a lineup with more contact, a little more speed. We can utilize that area and put the game in motion more and maybe bunt, hit and run, and if the other pitcher gives an opportunity, steal a base. Just play a game of smaller ball. I've known from Spring Training that at times this year we'll have to play this type of lineup. Might as well get used to it."
Lee has gotten off to a slow start with two hits in 25 at-bats so far.
"We'd like to get Derrek going," Piniella said. "He's been working. I'm confident he'll be swinging the bat the way he's capable."
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.