Fernando Alonso will not make a return to Renault next season because they cannot guarantee him a car that will compete for the Formula One drivers' title, admits team boss Cyril Abiteboul.
The Spaniard has made no secret of his frustration at McLaren, who's power problems with Honda are well documented.
Alonso's annoyance boiled over at the Belgian Grand Prix on Sunday as the two-time world champion retired for the fifth time this season.
During the race Alonso snapped at his team over the radio after receiving time gap updates he felt were unimportant, and went on to describe his car's lack of speed as "embarrassing, really embarrassing".
Alonso - who has a contract until the end of the season - hinted he would be forced to consider his future with the British team, particularly with his "stock value" higher than ever before.
A move to Mercedes to partner Lewis Hamilton, who he teamed with during his first stint at McLaren, had been mooted but any hopes of a Ferrari return were ended with Sebastian Vettel and Kimi Raikkonen both signing new deals.
It had been reported that Renault - with who Alonso won his two world titles - were planning on offering him an escape route instead, but that also now looks unlikely with Abiteboul unprepared to risk the chance of giving the 36-year-old another year of frustration.
"Things have to be compatible so that it can be a successful association, and not just because it has been a successful association in the past," Abiteboul told Autosport.
"It's the future that we're worried about.
"He has his dynamic, I think he has urgency to be in a position to be fighting for championships again.
"We know that it's going to take us a bit of time to have a car that can offer that, so clearly the one thing that I would not want is to have a frustrated Fernando in a Renault car, that's for sure."
Another former Renault driver, Robert Kubica, has also been linked with a return, but a lack of testing could see his chances disappear too.
"If we had no restrictions from the regulations there is a lot that we could do, by organising more testing, but it's exactly the same for a number of young drivers to try to make it into F1," said Abiteboul.
"There is a restriction in place, and it's not going to change for Robert.
"The main question is can he race again in F1? If the answer was a straightforward 'yes', you would probably not be asking me that question. But unfortunately it is not clear yet.
"A lot of people can be interesting. The fact that our car has become more or less the fourth car on the grid creates even more opportunities for us than we were maybe initially expecting."