Hulkenberg has been a driver at Renault since 2017 and has been an integral part of developing the team, helping it to a fourth-place finish in the constructors' championship last season.
"It's been a difficult call to make with Nico's contract coming to an end at the end of the season," said Renault managing director Cyril Abiteboul. "A decision had to be made on whether we wanted to stay put with our driver line-up or bring in a bit of change.
“It’s difficult because we all love Nico in the team. He has been instrumental to the progress that we have made.
"We have all struggled this season, but last year he has been instrumental in securing P4 in the championship. He had a good seventh place in the drivers’ championship, which is clearly the best that we can target.
“But frankly, when you make a decision like that, you don’t just look at pure pace. You also need to look at the collective dynamic.
"There is a dynamic that we need to restart and reset in the team. And for that, we also need to project ourselves into the medium-to-long-term future, not just 2020 but 2021 and what’s happening to his teammate and so on and so forth.
“So all of that, but in particular, the collective dynamic, what Esteban can probably bring to the team, probably starving for racing, being super happy to come back into racing, but also because he’s been out of a seat for a year. It’s all of these elements that we factored into the equation."
Abiteboul is confident that Hulkenberg will find another seat in Formula 1, with a move to Haas supposedly on the cards for the German driver.
"Plus also it's important to say that, it's not a certainty because we can't be certain of anything, but there's a high chance that Nico can continue his racing career," Abiteboul added.
Bahrain International Circuit - Winter testing