Audi kicked off the Rolex Series season in dominant fashion, with a near-sweep of the GT class podium. But surprisingly, only one of the German manufacturer’s R8 GRAND-AM cars has turned up this weekend, and even that one being a late addition.

Rolex 24 runner-up APR Motorsport will fly the flag for Audi this weekend, with Matt Bell and Ian Baas slated to drive the No. 52 entry, which will do battle with 15 other GT class cars in the production-based ranks.

After an impressive four-car factory effort at Daytona, only a single Audi R8 GRAND-AM is entered this weekend. (Photo: John Dagys)

Porsche leads the way in numbers, with no fewer than seven 911 GT3 Cup cars expected, including contending entries from Magnus Racing, Brumos Racing and Park Place Racing. The Texas-based squad sees Porsche factory driver Patrick Long return to action in its No. 73 entry as part of an expanded three-car effort.

Dion von Moltke, who heads in as the GT championship leader following his Rolex 24 win in the Audi R8 run under the Alex Job Racing banner, switches to a Muehlner Motorsports Porsche, with ALMS standout Kyle Marcelli as his co-driver.

While the late addition by Muehlner may surprise, the real threat will likely come from the Prancing Horses, with four Ferrari 458 Italia Grand Am cars entered.

Both AIM Autosport machines, including the No. 61 Ferrari of Max Papis and Jeff Segal, along with fellow reigning co-champion Emil Assentato, who is paired with Anthony Lazzaro in the sister No. 69 machine, are expected to be contenders.

Don’t count out the Scuderia Corsa entry of Alesandro Balzan and Alessandeo Pier Guidi, either, especially following an impressive Rolex 24 debut last month. The Ferraris, however, will have a 200 rpm reduction, following Balance of Performance adjustments also handed out in the GT ranks.

Also included in the round of changes is the Audi R8, which loses 200 rpm as well, while an rpm limiter has been added to the Stevenson Motorsports Camaro GT.R, Marsh Racing Corvette and flock of Porsches, which all ran unrestricted at Daytona.

Rounding out the field in GT are a pair of Turner Motorsport BMWs, unchanged from last month.

As it turns out, two of the three Rolex 24 class-winning teams will not be at COTA, as Napleton Racing’s Porsche Cayman, which took top honors in GX, is also absent.

The No. 38 BGB Motorsports Cayman of Spencer Pumpelly, Dr. Jim Norman and Jeff Mosing will go up against a pair of Mazda6s in the new-for-2013 category, which sees a meager three-car field this weekend.

Both of the SpeedSource-entered Mazdas, to be driven by Sylvain Tremblay/Tom Long and Joel Miller/Tristan Nunez, will be looking to rebound after early retirements with its new SKYACTIV-D clean diesel powerplants at Daytona.

Many teams will get their first taste of world-class circuit on Thursday during a Promoter Test Day, with official track activity kicking off on Friday. The GRAND-AM of The Americas presented by GAINSCO and TOTAL takes the green flag Saturday at 4 p.m. ET. Catch al the action on SPEED beginning at 5:30 p.m. ET.

John Dagys is SPEED.com’s Sportscar Racing Reporter, focusing on all major domestic and international championships. You can follow him on Twitter @johndagys or email him at