The WEC's announcement last weekend that it will return to the Nurburgring on July 16 next year goes against an understanding between the organisers of the two series to avoid clashes.

Ten of the 18 drivers that completed the second FE campaign have parallel 2016 WEC programmes, but the WEC's planned 2017 race date in Germany is the same weekend as the next FE season's Montreal double-header.

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The FIA and FE declined to comment when contacted by Autosport and no comment was available from the WEC, but it is understood discussions are under way to try to avert the clash that would affect key names like di Grassi and Toyota LMP1 ace and Renault e.dams' FE champion Sebastien Buemi.

Di Grassi, who will remain with Abt Audi Sport in the electric single-seater series next season and hopes to stay on Audi's LMP1 books as well, said the announcement of a clashing date caught him by surprise.

"It caught a lot of people out," he told Autosport. "There must be a way of making the races not clash.

"We're only talking about 20 weekends, it's a lot but there's still room to avoid clashes.

"We'll try to push the organisers and the FIA to find a solution.

"There are some constraints for local promoters and sponsors, it's a complex decision.

"It's in the best interests of everyone that we have the best drivers in both. It's difficult, but possible."

The WEC calendar remains provisional until the World Motor Sport Council approves it but the Formula E schedule announced earlier this month has already been rubber stamped by an e-vote.

Di Grassi said failing to avoid a clash would leave drivers with "a horrible decision" to make.

"Imagine the situation where you have a bad beginning of the WEC season and you're fighting for the FE championship," he said.

"I will then have to discuss with Audi what is the priority. Is it to fight for the championship or to do a WEC round that you could do with two drivers?

"At the moment it's not very clear what to do because Montreal is a double header."

FORMULA E AND WEC DRIVER CROSSOVER

* Partial FE campaign

** Partial WEC campaign

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