Former world champion Jenson Button has sent a warning to McLaren new boy Carlos Sainz, that he should not expect immediate success with his future team.
Until recently, Carlos Sainz was unsure on his future in F1 as his previous team at Renault decided not to renew his contract and instead signed Australia's Daniel Ricciardo for the 2019 season.
Sainz ultimately found a new home with McLaren after weeks of speculation, following two-time world champion Fernando Alonso's decision to call time on his career, opening up a position for the young Spaniard to fill for the foreseeable future.
Button, who claimed McLaren's last race victory on the final day of the 2012 F1 season in Brazil, has questioned whether the move is really right for Sainz.
"It's good - but is it stepping up, you know?" he told Motorsport.
"He was racing for the works Renault team, who are performing very well this year. He's moving to McLaren, whether it's the right move I don't know."
Renault have been performing better than McLaren this year, sitting fourth in the constructors' championship, whereas McLaren have again struggled to find form, currently seventh in the standings.
"I think he obviously didn't have the option to race at Renault this year with Daniel moving there, so I guess it's the right decision."
It would appear as though Button does see some of the sense in the switch, however, he did have some stark warnings for Sainz.
"I don't think the pace of the car is going to turn around for next year, it's going to be difficult, 'cause they've dropped a long way back," Button added.
"It is a big team, it is a team that has won multiple world championships, so they will find a way back.
"But it's going to take a little bit of time, I think." "He [Sainz] needs to understand, I guess, that it's going to take a few years of working hard and making himself feel present and making his opinion count, and hopefully moving the car forward."
Carlos Sainz will be aware of the issues with the current car, and along with Jenson Button's warnings will probably make him incredibly eager to prove his worth amongst F1's current crop of talent.
Button had one final warning for Sainz; "Obviously Fernando's retired, and he knows what he's doing, and he's getting the best out of the car pretty much every weekend.
"So it's always going to be a hard act to follow. But they wouldn't have chosen him [Sainz] if they didn't think he was worthy."