Wimmer will drive 23 races in the No. 29 Holiday Inn car and there's potential to put him in the No. 2 driven by Clint Bowyer for the remaining 12 Busch events so he can compete for a championship.
He also could run five to 10 Nextel Cup events if the organization doesn't go fulltime with a fourth team in NASCAR's premier series.
Wimmer has driven in two Cup events for RCR, finishing 31st in this year's Brickyard 400 at Indianapolis and 12th in the 2006 season finale at Homestead-Miami Speedway.
He spent the 2005 season with Bill Davis Racing and most of 2006 with Morgan-McClure.
He has six top fives and 12 top 10s in 19 Busch Series events for RCR this season and ranks 13th in points.
David Newton covers NASCAR for ESPN.com. He can be reached at firstname.lastname@example.org.