Midweek reports say that Dragon Racing will be fielding only one car in the IZOD IndyCar Series for the next few races, and possibly for the remainder of the 2012 season.

A lack of available Chevrolet engine deals is the cause, reports SPEED.com.

Although Dragon secured two last-minute Chevrolet engines for the Indianapolis 500 and was able to put both its cars out on the starting grid on Sunday, Chevy is unwilling to supply more than half the grid going forward and therefore currently has only one engine deal to offer to Jay Penske's team for the rest of the regular season.

Penske is reported to have decided to split the engine lease between his two currently full-time drivers, allowing Sebastien Bourdais to continue racing the #7 car in street and road courses, while Katherine Legge will drive the #6 car for the oval events.

That's not dissimilar to the arrangement that Bourdais had last year with Dale Coyne Racing, where he signed up for a street/road course deal only and the team then put Alex Lloyd in the car for the oval events. Bourdais was in any case due to miss the Milwaukee race in June in order to compete in the Le Mans 24 Hour endurance event.

While Bourdais has been delivering the better race performances out on track so far this season, Legge is bringing in the lion's share of the team's money through her financial backers, automotive dealership TrueCar, and it's not clear whether that sponsorship will now be spread between the #6 and #7 or will be lessened in order to reflect Legge's reduced race opportunities. Bourdais' race backing comes from Internet security company McAfee.

So far this season, Legge's best finish has been in 19th place at Long Beach, while Bourdais finished in ninth place at Alabama. Both results came while the team was still running Lotus engines. In their sole Chevy outing of the season so far at Indianapolis, Legge qualified in 30th position just 48 hours after receiving her new engine and completing her rookie orientation process, and went on to finish in 22nd place; Bourdais qualified in 25th place and finished just ahead in 20th. Both drivers were still running at the end of the race, albeit a lap off the lead.

Neither driver is in any serious contention in the IZOD IndyCar Series championship - Bourdais is currently 21st, Legge is 24th - so missing out on races will not make much material difference to their season.

Bourdais is likely to race at Detroit Belle Isle this weekend, and then take the rest of June off for Le Mans before returning to IndyCar for the Canadian rounds in Toronto and Edmonton in July, followed by Mid-Ohio Sports Car Course, Qingdao in China and Somona Raceway in August. The Frenchman's final race of 2012 would then be the Grand Prix of Baltimore at the start of September.

Legge will take the majority of races in June, with back-to-back events at Texas, Milwaukee and Iowa. She would then return for the final IndyCar race of 2012 at Auto Club Speedway in Fontana, California on September 15.

However, Jay Penske clearly remains hopeful that Chevrolet will be able to supply an additional engine lease later in the year, and has opted to retain all the personnel from the existing #6 and #7 car teams and not to streamline the operation into a one-team set-up for the time being.

Penske confirmed to the Indianapolis Star on Wednesday that the one-car line-up would be in place for at least the next two months while he worked on getting the additional lease.

The news means that the field will now consist of 25 regular entries for the foreseeable future, with 13 powered by Chevrolet and 11 with Honda engines, leaving HVM's Simona de Silvestro the sole Lotus representative.

Rahal Letterman Lanigan Racing had hoped to run a second car for 2011 GP2 Series runner-up Luca Filippi, but still faces problems with the Italian's financial backing together with the lack of an available Honda engine after team owner Bobby Rahal passed on his original lease option to Sarah Fisher Hartman Racing just before the first race of the 2012 season at St Petersburg.