Kurt Busch tops opening Auto Club practice

Busch, driving the Stewart-Haas Racing No. 41 Chevrolet, clocked a fast lap of 186.741 mph on the 2-mile California track. Sunday will mark his second Sprint Cup start of the year after making his return from a NASCAR-mandated suspension last weekend.

Busch said his team used a combination of race trim and a qualifying setup to set the fast time on the dusty D-shaped layout.

"It's always fast on Fridays when there's not a lot of rubber built up, so it changes radically on Fridays," Busch said. "And then Saturday, right in that last half hour of Happy Hour (final practice) for us, that's when you've really got to dial it in for race conditions on Sunday."

Denny Hamlin, Martin Truex Jr., Brad Keselowski and Jimmie Johnson completed the top five in preparation for Sunday's Auto Club 400 (3:30 p.m. ET, FOX). The session was marred by an early wreck for Greg Biffle and a late-session crash by Carl Edwards.

Brett Moffitt filled in as a last-minute substitute for Brian Vickers, who withdrew from the race Friday morning after doctors discovered a recurrence of his blood-clot condition, which has interrupted his racing career on three previous occasions. Moffitt drove the Michael Waltrip Racing No. 55 to the 27th-fastest lap in the 75-minute session.

Chris Buescher, a NASCAR XFINITY Series regular, was tapped to replace Moffitt on an interim basis in the Front Row Motorsports No. 34 Ford. Buescher, preparing for his Sprint Cup debut Sunday, turned the 29th-fastest lap of the 45 drivers to participate in opening practice.

David Ragan registered the eighth-fastest lap as he gears up for his fourth start of the season in the Joe Gibbs Racing No. 18 Toyota in place of Kyle Busch, injured in the XFINITY Series opener last month at Daytona International Speedway. Busch won the last two Sprint Cup races at Auto Club Speedway.

Defending Sprint Cup Series champion Kevin Harvick -- winner of the last two events, the opening two legs of the three-race West Coast Swing -- posted the 12th-fastest lap in the Stewart-Haas Racing No. 4 Chevrolet.

Biffle caused the first stoppage of first practice after he scraped the Turn 4 wall with his No. 16 Ford, just 2 1/2 minutes into the session. His Roush Fenway Racing spent the bulk of the practice making repairs to the right side of the car in hopes of saving their reserve racer.

Edwards also lost control out of Turn 4 in the final five minutes of the session, swerving back into the outside retaining wall and crumpling the right-front corner of his No. 19 Toyota. His Joe Gibbs Racing team unloaded its backup car ahead of Friday's Coors Light Pole Qualifying at 7:50 p.m. ET.

NASCAR officials announced that they took possession of the truck arm off the Circle Scott Racing No. 33 Chevrolet driven this weekend by Brian Scott after finding a technical infraction during opening inspection. Officials said they would take the part back to the NASCAR Research and Development Center in Concord, North Carolina, for further examination and would announce any findings early next week.

The cars of Alex Bowman, Matt DiBenedetto and Travis Kvapil were held 15 minutes on pit road because of violations during the previous race weekend at Phoenix International Raceway.

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