Sam Hornish Jr. prepares to get in AJ Allmendinger's car...

Sam Hornish Jr. prepares to get in AJ Allmendinger's car as a replacement driver in the NASCAR Sprint Cup Series auto race at Daytona International Speedway. (July 7, 2012) Credit: AP

CHARLOTTE, N.C. -- Penske Racing will use Sam Hornish Jr. this weekend at New Hampshire as the team waits for more information on suspended driver AJ Allmendinger.

Allmendinger was suspended by NASCAR for failing a random drug test and has until Tuesday to ask for his "B" sample to be tested. Penske Racing said in a statement Monday it is working with NASCAR to "follow its process and procedures." Allmendinger was suspended shortly before Saturday night's race at Daytona, where NASCAR officials were informed that his June 29 random test had come back positive.

NASCAR and Penske officials have not said what Allmendinger tested positive for, and Allmendinger has made no statement since his suspension.

Hornish was the emergency substitute for Allmendinger on Saturday night. He was pulled off a television set in North Carolina, where he was an analyst on a live broadcast, and flew to Daytona International Speedway. Hornish arrived right before the start of the race. A cut tire contributed to his 33rd-place finish.

Hornish is the natural replacement for Allmendinger, who is in his first season with Penske Racing. Allmendinger was hired in late December after the team suddenly split with Kurt Busch.

The 30-year-old former open-wheel driver got the No. 22 seat over Hornish, who joined the NASCAR part of the organization after moving from IndyCar following the 2007 season. Hornish struggled through three full Sprint Cup seasons but spent most of last year out of the car. He made only one Cup start and ran 13 Nationwide races.

This season, Penske has Hornish running the full Nationwide schedule. He has nine top-10 finishes and is fourth in the standings. But he wants to be back in the Cup Series, and was pleased to get the call Saturday to get back to Daytona, where he had finished 10th in Friday night's Nationwide race.

Hornish said it was his first time driving a Shell/Pennzoil car since 2003 in IndyCar. Shell sponsors the No. 22 car, and the company has not commented since the suspension.

Allmendinger is the second Sprint Cup Series driver suspended since NASCAR implemented its drug policy in 2009. Jeremy Mayfield contested his 2009 suspension, lost his fight in court and has not raced since.

According to Allmendinger's Twitter feed, he was appearing on behalf of sponsor Shell/Pennzoil less than two hours before the suspension was announced at 6 p.m. Saturday NASCAR clarified the timelines Sunday, saying its medical review officer first alerted Allmendinger of his positive test about six hours earlier. NASCAR was informed by the officer about 2:30 p.m. and met with Allmendinger and a senior Penske official shortly after. The suspension was announced 30 minutes after the driver meeting.

Just two weeks ago, Penske officials were adamant that Allmendinger was in line for a contract extension. Now, the suspension puts Allmendinger's future in jeopardy.

Shell has been pleased with Allmendinger's representation, and Penske officials likened his struggles this season to those of Brad Keselowski, who had a rough 2010 first season with the team but last year produced three wins and a berth in the Chase for the Sprint Cup championship.

More motor racing