Former F1 driver Emanuele Pirro does not think Sebastian Vettel is "having fun" in 2019.
Vettel has hit back at recent rumours that he could retire at the end of the year, telling Auto Bild: "I have no plans to stop."
But Pirro, who raced in F1 between 1989 and 1991, said the quadruple world champion is clearly struggling at present.
"He arrived in Ferrari in a beautiful way, winning the sympathy of many fans, but then slowly it goes away. Last year's Sebastian Vettel is the distant relative of what he was," the Italian told f1sport.it.
"We need to see if he can find himself, as he deserves to end his career differently. I hope he can find serenity in an environment that is as difficult as Ferrari.
"He needs to do things with ease. Anyone who plays sport does it with passion and fun. It is essential, and the difference between going pretty well and going very well, and right now Vettel is not having fun.
"Drivers are not supermen. In the athletic sense they are, but for the rest they are men with their weaknesses.
"Perhaps for Vettel, the Ferrari environment did not help him. It is the responsibility of those in charge to support and help their drivers," Pirro added.