The French driver said he had done his "fair share of the job" in attempting to lure the in-demand Spaniard to Alpine as successor to Esteban Ocon, who is set to depart at the end of the year.
"I think Alpine has good options on the table," Gasly told reporters ahead of this weekend's Hungarian Grand Prix. "At the end of the day, it's not up to me.
"I welcome the fastest guy out there. We all know who it is! At the moment, we have got to wait, but the team has three good options."
Asked specifically if he had spoken to Sainz, he said: "I did my fair share of the job! But ultimately, I believe in the project we are building with Alpine. I will always back the team. Now, it’s up to him to make his decision."
As the 'silly season' for future driver contracts draws closer, ahead of Formula One's traditional 'summer' break, teams are seeking to complete their planned driver line-ups for next year.
Sainz, set to leave Ferrari where he will be replaced by seven-time world champion Lewis Hamilton, has been linked to several other teams but most consistently with Alpine and Williams.
His delay in making a decision on his future has held up other moves in the market.
Gasly added that he was focused on recovering points-scoring form for Alpine at this weekend’s contest after a disappointing outing at the British Grand Prix.
"Firstly, I need to take the start and then actually race," he said, when asked about his hopes for Sunday's race at the Hungaroring, referring to gearbox problems that prevented him starting at Silverstone.
"Then, the car itself. We haven't really developed over the last few races so we have to maximise it.
"Others, like Haas, are making big strides and it is so tight in the midfield – every time a team brings a new part it re-shuffles the order.
"But, we know we have to try to compete. It’s not easy without upgrades on the car."
