Michela Cerruti to miss Auto GP finale due to back injury

The 27-year-old, who became the series' first female winner at Imola earlier this year, tested at the former Portuguese Grand Prix Formula 1 venue earlier this month in preparation for the event, but has now had to withdraw.

"Following a medical check, I was strongly advised not to race due to a recurring back injury," said Cerruti.

"This is an issue I had been dealing with for a while.

"In order to solve the problem and be at 100 per cent for the next season, the doctors advised me to stop and undergo a surgery procedure that will keep me parked for the next month."

The Super Nova driver is currently sixth in the Auto GP standings, and team manager John Sears said Cerruti's absence was a big disappointment.

"The whole team received this news with a heavy heart as we have built a great relationship with Miki and thoroughly enjoyed working with her this year," he said.

Cerruti expects to be fit to resume her parallel Formula E programme with the Super Nova-run Trulli operation in Putrajaya next month.

Other Auto GP line-up changes for the Estoril weekend include GP3 racer Luis Sa Silva joining Zele, and Shinya Michimi making a third appearance of the season with Euronova, which has run a variety of drivers alongside already-crowned champion Kimiya Sato during 2014.