Spanish Renault 3.5 stars Carlos Sainz Jr and Roberto Merhi are both in the frame to make their F1 debuts with Caterham before the end of the season.

It’s believed that they are both likely to be given an opportunity to drive the car occupied by Andre Lotterer this weekend.

As noted here some time ago Sainz came into the frame around the time of the British GP when Red Bull discussed putting him in the Caterham for the rest of the season. Caterham uses a Red Bull gearbox, while team advisor Colin Kolles did a similar deal to put Daniel Ricciardo in an HRT in 2011. However it was decided to allow him to concentrate on Renault 3.5.

Merhi, who won the 2011 Euro F3 title before spending two years in the DTM with Mercedes, has been in the Caterham motorhome at Spa this weekend.

Sainz and Merhi currently lie first and second in the Renault 3.5 series. The championship has three more weekends to run, none of which clash with Grands Prix.

The team could face a problem however as the rules specify that only four drivers can be used per season, and it has already used three. The likelihood is that the FIA will only be flexible in the case of genuine force majeure.