Jack Nicklaus believes a fit Tiger Woods can play for another decade and eclipse his record of 18 major titles.
Woods is expected to make his long-awaited return to golf at the Hero World Challenge in the Bahamas on Thursday, 15 months after his last appearance on the PGA Tour.
The 40-year-old has been sidelined after requiring back surgery and aborted a planned comeback at the Safeway Open in October due to fears over his "vulnerable" game.
But he looks set to finally restart his career this week and was praised by Justin Rose after playing nine holes with the Olympic gold medallist.
Woods himself was in confident mood ahead of the first round and Nicklaus believes the former world number one still has a lot to achieve.
"I've talked to Tiger a reasonable amount in the last year or so," Nicklaus told BBC Sport. "He keeps saying he is fine, he looks good, he's ready to play, yet he hasn't come back to play.
"That probably is the five inches between his ears that is the part that he's having trouble with.
"And he has got to re-evaluate that and find out what's going to happen to him and how can he mentally get himself back into the idea of playing golf again.
"I think Tiger has got the physical and the mental ability to be able to handle that but then he has got to go out and do it. We'll see, I wish him well.
"I've always thought that he's got at least another 10 years of good competitive golf in front of him, if he's healthy and as talented as he is."
And when asked whether Woods can add to his 14 major titles and go past Nicklaus' record the 76-year-old added: "I don't think anything is safe."
In Woods' absence a plethora of younger players have come to the fore, something Nicklaus believes is good for the game.
"While Tiger's been gone I think we've had a pretty good run of a lot of very good young players who have come forward," Nicklaus said.
"Golf is not on one person's shoulders any more. It would be nice to have Tiger come back and play well, I think he'd be great for the game of golf and he's got some great competition with the young guys out there today.
"Even a couple of the old guys have played pretty well, you know Phil Mickelson [who is 46] hasn't exactly disappeared."