Sainz and Hülkenberg formed a partnership at Renault for about a year and a half, with Sainz replacing Jolyon Palmer at the French works team during the 2017 season.
The duo formed a good partnership and won the midfield battle in 2018 together, but Sainz was replaced for the 2019 season by the incoming Daniel Ricciardo, who Renault had lured away from Aston Martin Red Bull Racing.
Now, Hülkenberg is the one being replaced, as Esteban Ocon has been announced to take the 31-year-old's place in 2020. With Haas announcing they will retain both of their drivers for 2020 as well, seats are running out for the one-time pole-sitter.
Although they're not teammates anymore, Sainz still thinks very highly of Hülkenberg.
"I think everyone knows what Nico brings to the grid, I don't think I need to explain myself much," the Spaniard told Autosport when quizzed about the Le Mans winner.
"But, as we know, in Formula 1, it's not always the talent or what you're capable of doing on track that is predominant.
"There's a lot of things that can be taken into account, other than your talent and how quick you are.
"If it was speed and talent, he should be on the F1 grid until whenever he wants."
Seats at Williams and Alfa Romeo Racing could still be available for Hülkenberg, although it seems unlikely that either team would opt to go for Hülkenberg. Could this be the end of his Formula 1 career?