New York ? Reigning Nextel Cup champion Kurt Busch is changing teams, moving from Roush Racing to Penske Racing South. The only question is when.

Busch signed a multiyear contract to drive for Penske starting in 2007 and asked to be released from his current contract with Roush Racing, apparently in hopes of replacing retiring Rusty Wallace next season. In a statement, Roush said the team would wait for “an indefinite period” before making a decision on Busch’s request to leave after this season.

“Yeah, we have signed him up for 2007,” Penske team president Don Miller said Tuesday. “As for anything else, the lawyers tell us we can’t really comment.

“Kurt Busch is a great driver, and Ryan (Newman) said he is looking forward to having him as a teammate and working with him.”

Newman is the current teammate of Wallace, the 1989 series champion, who is retiring at the end of the 2005 season, leaving a vacant seat in the No. 2 Dodge.

Busch attended the Cubs-Reds baseball game Tuesday at Wrigley Field in Chicago.

“There’s still so much more work to be done in the meantime. I’ve got an opportunity to win a championship in 2005, as well as 2006, for whomever I drive for,” Busch said. “Roush Racing has given me the best equipment to go and do so, and I’m for the opportunity of what these next five races mean, which is to get into the playoffs and, of course, the Chase.

“There’s times for change, and then there’s times for staying put,” he added. “I haven’t made my 2006 plans very clear yet.”