Earnhardt's absence Saturday started a merry-go-round of driver changes that opens up interesting scenarios for the next few weeks.

Upon learning of Earnhardt's need to rest and recover, team owner Rick Hendrick called on Smith, who was scheduled to begin driving this week for Phoenix Racing. There was a vacancy at Phoenix because of the departure of Kurt Busch, who is moving into Smith's old ride at Furniture Row Racing.

When Smith accepted Hendrick's invitation to drive Earnhardt's regular ride -- that decision took him about a millisecond -- it re-opened the cockpit at Phoenix, and it was filled Saturday by the return to NASCAR racing of AJ Allmendinger.

In any other week, Allmendinger's reappearance would be the major story. He was suspended by NASCAR in July after failing a drug test and was reinstated to competition recently after completing NASCAR-mandated rehabilitation. Saturday night marked his first race since the suspension.