Former world number one David Duval has advised Rory McIlroy to rest for the long-term good of his golf.

The American outlined his concerns for the Northern Irishman's health after watching McIlroy struggle to make the cut in the US PGA Championship at Quail Hollow last week.

"He needs to go home," said Duval in his role as a TV analyst.

"He needs to stop playing right now. He's hurt and I am watching his golf swing deteriorate."

Duval was speaking from experience, having seen his own performance decline dramatically through injury following his sole major title in 2001 - culminating in the loss of his tour card in 2011.

He added: "If only I could go back and tell myself 18-20 years go when I started having those problems, 'Stop, get healthy.'

"He could do himself a big service. He's always had a little bit of a hitch with the driver in terms of flattening out a little but it is getting a lot more pronounced right now and I think that is due to that rib injury."

McIlroy is wrestling with the career-defining choice between carrying on through the FedEx Cup play-offs or taking the rest of the year off to allow his niggling rib injury heal.

He said: "Look, I don't know what I'm going to do.

"You might not see me until next year. You might see me in a couple of weeks' time. It really depends."