DOVER, Del. — The interim crew chief for Dale Earnhardt Jr. is taking over for the Cup race at Dover, a week earlier than originally planned.

Lance McGrew was scheduled to work with Brad Keselowski on Sunday, but he failed to qualify, freeing up McGrew to call the shots on Earnhardt's slumping No. 88 team.

McGrew said after the driver's meeting that that the decision was made by owner Rick Hendrick and Hendrick competition director Ken Howes on Saturday night.

"The powers that be decided to go ahead and give us a week head start," McGrew said.

McGrew had been scheduled to start next week at Pocono Raceway.

Team manager Brian Whitesell, who was scheduled to be the crew chief, will assist McGrew. Earnhardt starts 22nd at Dover International Speedway.

"It's the most challenging assignment anybody's ever had, just because of the profile," McGrew said. "Not only is it important for Dale Jr. to run for Hendrick Motorsports competitively, I think it's important for the sport. He has such a tremendous amount of fan base, you don't want to know people are turning off the TV at home because Dale Jr.'s not running good."

Hendrick removed Tony Eury Jr. from his position as Earnhardt's crew chief Thursday in a move designed to spark Earnhardt's season. Earnhardt is 19th in points and coming off a season-worst 40th-place finish at Lowe's Motor Speedway.

The longtime Earnhardt-Eury pairing only produced one win in 48 races with Hendrick, and this season saw a flurry of pit-road gaffes and setup miscalculations that has a spot in the Chase for the championship looking like a long shot.

Earnhardt is a whopping 203 points out of the 12th place cutoff for the Chase. He's had three top-10 finishes and six finishes of 27th or worse.

"Today I told him if we run 10th to 15th, it's a win, and we'll just keep building on that," McGrew said.

Earnhardt and McGrew worked together in the Nationwide Series, and have talked extensively the last two days to get up to speed for the race.

Former Hendrick driver Kyle Busch took a shot at Earnhardt on Friday about the perception that his poor finishes were never his fault, always the crew chief.

Earnhardt left his seat next to McGrew at the driver's meeting and took one in the front row for a brief chat with Busch. The two spoke for a little more than a minute before Earnhardt returned to his original seat.