Maddux was acquired by the Dodgers from the Cubs two years ago and went 6-3, a key reason why the Dodgers rallied to qualify for the playoffs as the NL Wild Card.
This time they need him to replace Brad Penny, who is back on the disabled list after making only two starts over the past two months because of persistent shoulder problems.
"It's very rare that you get the opportunity to add a pitcher like Greg even one time, let alone twice," Colletti said in a club release. "He's one of the greatest pitchers of all time and we've already seen what he can add to a team, both on the field and in the clubhouse."
To get Maddux, the Dodgers sent the Padres two Minor Leaguers to be named or cash considerations, probably after the season ends. The teams will share the cost of the remaining $2.3 million of Maddux's $10 million contract. Maddux had a no-trade clause, but told the Padres he would waive it for the Dodgers so he could remain close to his Orange County home.
Maddux went a tough-luck 6-9 with 11 no-decisions and a 3.99 ERA for San Diego. Penny's spot comes up again on Saturday in Philadelphia, although Maddux could be slipped into the rotation as early as Wednesday night against Colorado. He last pitched on Friday night, when he allowed the Phillies one run over seven innings and lost, 1-0.
He has 353 career wins, four Cy Young Awards and 17 Gold Gloves. He joins a rotation that includes Derek Lowe, Chad Billingsley, Japanese rookie Hiroki Kuroda and 20-year-old rookie Clayton Kershaw.
Talks with the Padres for Maddux had reached an impasse at the recent Trade Deadline. But they were revived on Monday after Colletti watched James McDonald struggle in a Sunday night start for Triple-A Las Vegas that amounted to an audition to replace Penny in the rotation.
Colletti has a long history with Maddux from their days with the Cubs, when Maddux was just starting his career. At the Trade Deadline in 2006, Colletti sent infielder Cesar Izturis to the Cubs for a 40-year-old Maddux, who nearly threw a no-hitter in his first game for the Dodgers and went 6-3 with a 3.30 ERA as the club reached the playoffs.
"He's not what he was when he was winning Cy Young awards, but he'll still keep you in the game," Colletti said two years ago. "He's one of the smartest players I've ever been around. He'll figure out a way."
Even at his age, Maddux not only is considered an upgrade on the mound for a pressure-packed final six weeks, but an undisputed leader in the clubhouse. Lowe often talks about the positive effect Maddux had on him that year. Lowe went 8-1 over the final two months of that season and hasn't had a similar run since.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.