ATLANTA -- Derrek Lee can use an extra day of rest.
The leading hitter in the major-leagues and an All-Star first baseman for the Chicago Cubs, Lee learned Wednesday that results of an MRI on his left shoulder were negative.
"It's nice to find out for sure it's nothing serious," Lee said. "All along we pretty much knew it wasn't, but it's reassuring. It's something I've been playing with, so, like I said, we knew it wasn't serious."
Chicago manager Dusty Baker, whose team will play a day-night doubleheader Thursday after heavy rain postponed Wednesday night's game against the Atlanta Braves, doesn't know when Lee will return to the lineup.
Baker's lineup card Wednesday had Todd Walker starting at first base and Jose Macias in Walker's usual spot at second. Lee, who has a .377 average, felt a twinge of pain in his shoulder as he struck out in the first inning Tuesday and soon left the game.
"I saw him wince on a couple of swings," Baker said. "It's always frightening when one of your front-line guys comes up wincing."
Lee, who bats and throws right, indicated it's too early to tell if will sit out his first All-Star Game on Tuesday in Detroit. He received more than 3.5 million votes to lead the NL.
"I haven't thought that far," Lee said. "I'm just trying to play tomorrow. Players play with inflammation all the time. If we didn't, we'd probably never play. You have to deal with some stuff."
The Cubs will start Mark Prior (5-2) in the 1:05 p.m. game Thursday against Horacio Ramirez (7-5). Jerome Williams (1-3) will face Atlanta's John Smoltz (9-5) in the regularly scheduled 7:35 p.m. game.
Cubs trainer Mark O'Neal indicated the team will use extra caution with Lee, whose test results showed inflammation of the joint, but no serious concerns.
"We're going to treat it with our standard medications," O'Neal said. "We're going to treat it with our therapy. Basically right now we're listing him as day-to-day. Until he is able to swing with minimal discomfort, we're not going to put him back out there."
O'Neal discussed the results with Cubs general manager Jim Hendry, and both agreed that Lee might miss Thursday's games, too.
"My plan would be to give him probably today and tomorrow off," O'Neal said. "That way we don't have to do anything until Friday night in Florida. That's purely speculative. He may be in there tomorrow night. We just have to see. It depends on how he feels."
Lee, the NL player of the month in April, indicated his shoulder has periodically bothered him since 2003, his final season with the Florida Marlins.
"Derrek's a little upset with us for even taking him out last night," O'Neal said. "We're just going to have to see. Let the coaches watch him take BP. Make sure they feel comfortable with the swings that he's taking and go from there. It's a subjective call on Derrek's part."
- Braves manager Bobby Cox said OF Brian Jordan will go on the disabled list Thursday with an injured left knee. Top prospect Jeff Francoeur, whose contract will be purchased from Double-A Mississippi, is likely to be in the lineup Friday in place of either left fielder Kelly Johnson or right fielder Ryan Langerhans.