The Chicago Cubs traded first baseman Derrek Lee to the Atlanta Braves for three pitching prospects, the team announced Wednesday.

"It just felt right," Lee said. "The main thing is we have six weeks left and Atlanta is in first place, and they're playing great baseball.

"I understand what [Cubs general manager Jim Hendry] is trying to do over here."

Lee, who is presently dealing with a bulging disk on his lower left side, received an epidural Monday to relieve the pain and will not be ready to play again until Thursday.

His first game with Atlanta may be back in Wrigley Field this weekend as the Braves open a series with the Cubs on Friday.

"I had a great time here," Lee said. "I grew as a player, grew as a person, but I didn't achieve the ultimate goal [of winning the World Series], so that part is disappointing. The rest of my experience was nothing but positive."

Braves scout Jim Fregosi watched Lee hit four home runs during a series in St. Louis last weekend. Fregosi reported back to general manager Frank Wren that Lee was swinging the bat as well as he has all season, according to a source.

The Braves sent three pitchers to the Cubs, right-handers Robinson Lopez, 19, and Tyrelle Harris, 23, and lefty Jeffrey Lorick, 22. Lopez and Lorick were both playing at Class A Rome, while Harris has pitched at three levels this season, most recently for Double-A Mississippi.

Atlanta also received cash considerations in the deal. That's probably to cover some of the nearly $3.3 million that Lee is still owed this season.

Atlanta lost All-Star third baseman Chipper Jones for the season with a torn ACL on Aug. 10. First baseman Troy Glaus, a former third baseman, could play some third with Lee's acquisition.

"It doesn't get any better," Jones said. "Outstanding character guy. Outstanding player. Defensively at first base, he's top-notch. And he gives us another right-handed presence in the middle of our lineup."

General manager Frank Wren wants Glaus to rest his legs for a week, then head to Triple-A Gwinnett to get in some work at his former position, third base.

Lee has not had his best season; his .251 batting average entering Wednesday's game is well below his .282 career average and the .306 he hit last season. He is in the final year of a five-year, $65 million deal with the Cubs.

"He's had a tremendous career here, except for the year [2006] with his wrist injury," Hendry said about Lee. "He's performed like an All-Star player, and an All-Star teammate, and an All-Star to deal with from the front-office side.

"It's unfortunate we got ourselves in the spot we're in now. The overall situation we're in makes us all somewhere between miserable and sad every day."

Because he's been in the majors 10 years and five with the same team, Lee could have refused any trade. He recently rejected a deal to the Los Angeles Angels.

"The Angels were close, but it wasn't right then," Lee said. "This time seemed like it would work."

Lee said Hendry approached him with the trade on Sunday, and he accepted on Monday.

Braves All-Star second baseman Martin Prado came off the disabled list Tuesday and moved over to third to fill in for Jones. By acquiring Lee, the Braves have expanded their roster options as they try to hold off the two-time defending NL champion Philadelphia Phillies.

The 34-year-old Glaus has put up solid numbers (.239, 16 homers, 70 RBIs), but the Braves said his body is worn down from the grind of the season -- especially since he missed most of last season recovering from shoulder surgery. He got off to a slow start, then hit .330 with six homers and 28 RBIs in May to earn NL player of the month honors.

He apparently jammed his legs in a victory over the Dodgers on Monday night, speeding up the need to acquire additional offensive help.

"His legs just didn't hold up," Wren said, though he was quick to praise Glaus' contribution. "Quite frankly, we're not in position to make a trade like this without Troy Glaus. He carried us."

Limping to the finish of another disappointing season, the fifth-place Cubs had little to lose by dealing Lee. They already had traded pitcher Ted Lilly and infielder Ryan Theriot to the Dodgers, and sent infielder Mike Fontenot to San Francisco.

Bruce Levine covers baseball for ESPNChicago.com and ESPN 1000. Information from ESPN.com senior baseball writer Jerry Crasnick and The Associated Press contributed to this report.