Hoping to return for the ladder leaders' finals run, Yeo put off a medical procedure after hurting himself in Friday's disappointing loss to the Warriors.
"I know he's very optimistic," coach Ivan Cleary said.
"Just looking at him and knowing the kind of guy he is, I think we all should be as well."
The four-time premiership-winning lock is likely to require surgery, though the exact timing is likely to depend on how his injury responds to initial rehabilitation.
Surgery immediately after the season would likely have Yeo back at Penrith pre-season training around the new year.
But complicating matters, Yeo had been set to captain the Kangaroos at the World Cup, which begins only 11 days after the NRL grand final in October.
That would conceivably delay Yeo's surgery, and his return to the Panthers, by more than a month.
The Panthers are not concerned by the prospect of Yeo causing further damage to his injury at the World Cup, with function and pain both bigger concerns.
"I don't think he could do much more damage," Cleary said.
Yeo will face no opposition from the Panthers if he is fit and keen to prioritise his international duties over immediate surgery.
"He can do whatever he wants," Cleary said.
"We back all our players, representative football is part of the make-up of our game.Â
"The World Cup doesn't come around every day. He and we will make the right decision at the right time."
The Panthers are hopeful Dylan Edwards can be brought into their starting side for Thursday's top-of-the-table clash with the Sydney Roosters.
Rookie fullback Jaxen Edgar has been named to start for a fourth consecutive game, but Edwards is nearing recovery from a shoulder injury.
"'Jax' is just starting on his journey, pretty happy with how he's going, but it'd certainly be nice to have Dyl back in the side as well," Cleary said.
The Panthers could also be forced into reshuffling their halves again, potentially opening up game time for Jack Cole or out-of-favour Blaize Talagi.
Five-eighth Jack Cogger missed last week's trip to Auckland to await the birth of his child, but as of Wednesday morning, his wife had not yet given birth.
"There is a chance (Cogger misses another game)," Cleary said.
"Sometimes some things are more important than footy."
Penrith's first-choice five-eighth until round 22, Talagi was axed ahead of a big win over Canberra, with his defence on the left edge a particular cause for concern.
But Cleary would not rule out a recall on the run to finals.
"Blaize is absolutely right in the mix of our plans going forward," the coach said.
"He's just on a bit of a journey, that's pretty normal in terms of playmakers early in their NRL career."
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