Bath fly-half Rhys Priestland believes he is not eligible for Wales after staying in the English Premiership.
He says he would be prepared help out in a World Cup injury crisis, but does not think it would arise.
“I don’t think I am eligible,” he told BBC Sport Wales “That is because of the 60-cap rule.”
He added: “I honestly don’t know what the situation is, I did speak about it last year but I could not get any answers so I assume (I cannot play) because I only have 50 caps.”
Patchell picked up a head injury against Ireland but has flown with the squad, with Jarrod Evans the direct replacement.
Priestland could be in contention to be the next fly-half in line if there were any further injuries.
“If you asked anybody they would want to play at a World Cup,” said Priestland.
“But I honestly don’t know what the situation is.”
There has been confusion whether the ruling applies to Priestland, because he was not officially offered a deal by a Welsh region before re-signing with Bath.
In that three-month period, Priestland admitting he was considering a return to Wales after joining Bath from Scarlets in 2015.
But the uncertainly over the future of the Welsh regional game – with an aborted merger of Ospreys and Scarlets and rumours of a new region in the north – stopped that.
“It was an option and I did speak to a few people, but the conversations did not get any further than that,” said Priestland.
“It was an absolute shambles and carnage back there. Players were out of contract and did not know what was going to happen so there was a time pressure.
“It took so long. I had a couple of months left on my contract and was under pressure from other people to make decisions and I could not get any answers.
“Hopefully that is sorted now back in Wales and they can have a bit more stability.”
Priestland admits he is happy with how his club career worked out after signing with Bath until the end of the 2020-21 season.
“I have loved my time at Bath,” said Priestland.
“It is a great club and I am happy I am staying here for two years.”
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All pictures via Huw Evans Images.