Ramirez has had trouble with his legs. He had a severe left quad strain last year, and this year, he injured his right quad in late July.
"Whether or not he comes back [this season], this gives us five to six weeks to work on him before he leaves here," O'Neal said.
The Cubs plan to design an offseason workout program for Ramirez, who spends his winters in the Dominican Republic.
"He's had a large number of lower extremity injuries and we want to prevent those if we can," O'Neal said. "Our goal this winter is to prevent these things from happening."
Ramirez was batting .302 with 31 home runs and 92 RBIs this season before he was hurt.
Roster moves: The Cubs will call up pitcher Jermaine Van Buren and outfielder Matt Murton from Triple-A Iowa on Tuesday. Van Buren, 25, will take Kerry Wood's spot in the 'pen. The hurler set Iowa's single-season record this year with 24 saves, and he posted a 2.01 ERA in 51 games. The right-hander, who was a second-round pick by Colorado in 1998, has struck out 63 in 53 2/3 innings.
Wood was scheduled to undergo arthroscopic surgery on his right shoulder Wednesday in Cincinnati.
Murton already has appeared with the big league team, getting called up on July 8, and batted .339 (19-for-56) in 25 games.
Cubs general manager Jim Hendry said they will add a few more Minor League players Thursday when teams can expand their rosters beyond 25. The Cubs already have a lot of youth on their roster.
"In my mind, Corey [Patterson] is still young. Our whole bullpen is young," Cubs manager Dusty Baker said. "We've been having 'young' out there for a long time and if not young, then inexperienced from [Roberto] Novoa to [Michael] Wuertz to [Will] Ohman to [Todd] Wellemeyer. Half our team is either inexperienced or young."
Baker will pick the right spot for the kids like Murton and shortstop Ronny Cedeno.
"I believe in matching young guys up so they have success," Baker said. "I've seen young guys get ruined.
"We've still got to win games, too. This isn't some great experiment. I play everybody on my team. They're going to get at-bats, big time."
Extra bases: Baker had planned on giving Derrek Lee Monday off. Lee hit two home runs Sunday to end an 0-for-8 mini-slump. "Every time I want to give him a day off, he gets hot again," Baker said. "As soon as he looks like he's fading, he'll wake up and hit two home runs. We've got off-days coming up soon." Expect to see Scott McClain at first to give Lee a break. ... Baker denied showcasing players as teams approach the Aug. 31 deadline to set playoff rosters. "I'm not playing them to showcase them," he said. "Jim [Hendry] doesn't tell me who to play. [Giants GM] Brian Sabean doesn't tell me who to play. That's not trying to win to me. I'm trying to win. That's all I know. If there's any game to play, I try to win, whether it's against you, my momma, my daughter, my son. I don't want to get beat." ... Todd Walker needs five home runs to reach 100 in his career.
Minor matters: Double-A West Tenn edged Chattanooga, 3-2, on Sunday in a game continued from Saturday. Jon Searles picked up the win, giving up two runs in four innings of relief. Adam Greenberg was 1-for-3 and Ryan Theriot was 3-for-4. West Tenn lost, 5-2, to Chattanooga in the second game. Ryan O'Malley gave up one earned run and three hits over five innings. ... Sean Gallagher won his 14th game in Class A Peoria's 4-1 victory over West Michigan on Sunday. Gallagher threw 7 1/3 scoreless innings, striking out eight and giving up three hits. ... Donald Veal threw four scoreless innings in Class A Boise's 4-0 win over Tri-City.
On deck: Mark Prior (9-5, 3.68 ERA) will start Tuesday in Game 2 of the three-game series against the Los Angeles Dodgers at Wrigley Field. Prior is 2-2 with a 5.10 ERA in August. Brad Penny (6-8, 3.75 ERA) will oppose.