The Spaniard is currently weighing up opportunities he has from Williams and Sauber/Audi next year, with both squads clear that he is their number one target for a 2025 contract.
While the Sauber offer has been there for a while, Williams has been pushing hard in recent weeks to convince Sainz it can deliver him a good enough package.
Sainz is well aware of how determined team boss Vowles is to get him, but says that the open overtures are not going to rush him into making a call.
“I appreciate obviously James' interest and kind words that he has always towards me,” said Sainz. “The same can be said about how I feel towards him and his team.
“But the reality is that I haven't made up my mind yet about where I'm going to go next year because, as I said in the press conference the other day, I'm too focused.
“Right now, my head is too focused on every weekend that we're doing. Weekend in, weekend out, I'm fighting for podiums or wins. So it's very difficult to put your mind in the future when you have such an important weekend coming up all the time.
“I'm going to need some time to sit down with my management, with myself, have a conversation with myself and then decide where I want to go. But right now, there's nothing decided.”
Asked if he could wait until the summer break or he wanted his future sorted before then, Sainz said: “I don't know. I don't know if I can wait or if the decision will come earlier. I honestly don't know at this point in time.”
Autosport revealed at the Monaco Grand Prix that Williams is in advanced talks with Sainz as it bids to lure him onboard as Alex Albon’s team-mate for next year.
And although the squad is not fighting for podiums right now, the team thinks it can give Sainz an environment in which he can thrive.
Speaking to Sky Sports F1 about why Sainz should join Williams, Vowles said: “There's a reason why I'm here: Williams isn't the same Williams it was three years ago.
“And by the definition of the fact that we are even talking to Carlos, it shows you that we've changed our approach.
“We want two world-class drivers to be a part of our stable going forward. We want the world to realise that we're here and we're serious. We're investing what it takes to be back at the front.
“In 2026, we have one of the best power units, if not the best power unit coming to our car. We'll announce shortly, I hope, but there's around 30 incredible people from other teams joining our organisation that we've been gathering across the last 12 months. The world is changing.
“Someone like Carlos would feature very highly in that regard in terms of the grand picture of where we are. Of course, the difference is he has the choice of whether he wants to come here or not. That's his to make.”
