"It's one of those things, it's entirely down to him," Campbell said. "It's not going to be your usual 'my body's aching and I can't do this anymore, I'm constantly getting injured'. He's so dedicated still. If he wanted to play for another three, four, five years, I'm sure he's more than capable of doing it."

Campbell also praised Ronaldo's commitment to improvement, revealing that he was always the first to arrive on the training pitch and the last to leave. "He lived and breathed football," Campbell said. "Everything that he did was in preparation for either his next training session or his next game."

Ronaldo is currently under contract with Al-Nassr until after his 42nd birthday and is likely to continue playing for several years as he chases down 1000 career goals.

Ronaldo's dedication to football is evident in his training habits, and Campbell believes that he has the potential to play for many years to come.