The Brazilian, who was the standout LMP1 driver in Audi's roster in 2016, has been looking for a Le Mans berth since the German marque announced it was ending its LMP1 programme last autumn.

Di Grassi told Motorsport.com that a fifth appearance at La Sarthe was “highly likely in either LMP1 or GTE Pro, which are the only two categories which interest me.”

Should it come off, an LMP1 drive would almost certainly be as one of the drivers in the third Toyota TS 050 Hybrid, which currently has just Stephane Sarrazin confirmed as one of the three drivers.

Motorsport.com understands that some dialogue between Toyota and Audi has taken place, but that a GTE Pro class seat for di Grassi is more likely.

“There are limitations on who Lucas could drive for,” Audi motorsport boss Dieter Gass told Motorsport.com.

“Obviously it is much easier for us to release a driver for a private entry rather than a works entry. We also look at the level of competition, so for example we wouldn’t want him driving for a rival brand.

“Le Mans in any car will depend on the kind of car it is. We have released drivers like Marcel [Fassler] and Mike [Rockenfeller] to Corvette for Daytona and they could do other races this season."

The details of di Grassi’s Audi LMP contract, which was secure for the 2017 season, is currently being “put in to the right format,” Gass added.

“Lucas’ WEC contract has not been cancelled so he still has an Audi contract. At the same time he has another contract with ABT for Formula E.

"So currently we are working on making one out of two but we haven’t finalised yet the new contract for what could do apart from Formula E.

"We do have the agreement with him that he will continue as an Audi factory driver but we just have to put it in to the right format.”

A return to Macau for di Grassi, who last raced at the Asian street track in 2012 and won the F3 Grand Prix event there in 2005, could also be on the cards later this year.

“We are looking at the possibility of using [di Grassi] in our GT programme so this could happen,” said Gass.

“We always remember that he is one of the guys who is really fast around Macau, but this is not finalised yet. These are things we are looking at.”