Sergey, however, is now a frontrunner in GP2, where at Hockenheim he took the joint lead in the championship standings.
Sirotkin is also a test driver for the French works team Renault, thanks to his backing by the Russian programme SMP Racing.
His father Oleg told Russian radio Sport FM that Sergey taking the lead in the GP2 championship is significant.
"GP2 is the last step before formula one so it is really a merit to his efforts and SMP Racing," Oleg said.
"As for Renault, Sergey will still do some formula one tests and we are in fact talking about Sergey getting a chance with the team.
"The first thing to do is minimally the top three in the GP2 championship, but it is better to win. The Russian market is very important to Renault, and the presence of a Russian driver I think would be very good for them," he added.