Both teams beat the odds and made the field for the first two events -- the Daytona 500 two weeks ago and the Auto Club 500 last weekend in Fontana, Calif. -- but neither car came close to making the 43-car field in Friday's qualifying session at Las Vegas Motor Speedway.
The entry list at LVMS had 51 cars, meaning eight drivers would go home after qualifying. Mayfield had trouble getting through the technical inspection and barely made it to pit road in time to make a qualifying attempt. He was 12th among the 15 non-qualified drivers. Riggs was 13th.
Mayfield started his own team last month with the No. 41 Toyota. Riggs is driving for Tommy Baldwin Racing in the No. 36 Toyota. Both teams are hoping to run the full 2009 season, but missing a race hurts their chances.
Failing to qualify makes it more difficult for Mayfield and Riggs to rank in the top 35 in the Cup standings. The top 35 teams have a guaranteed spot in the field. It's based on 2008 owner's points for the fist five races, but switches to 2009 points after the fifth race this season.
Terry Blount covers motorsports for ESPN.com.