Bairstow sustained the injury during the limited-overs section of England's tour and had to watch on as Ben Foakes was called into the side and made a brilliant start to his Test career. Not only did Foakes become only the second England wicketkeeper to make a century on Test debut - Prior was the first - but he equalled a Test record by claiming a dismissal with just his second delivery in the field. He was also the first England wicketkeeper to score a Test century in Asia.
All that has left Bairstow facing the possibility that he may struggle to regain his preferred place behind the stumps. But while Prior understands Bairstow's enthusiasm to return, he has cautioned him against trying to do so too early.
"You don't want to rush back from the injury he has," Prior said. "I've mentioned this to Jonny. It can just create a lot more hassle.
"It's not so much the forward and back and linear movement that will be an issue for him, it's going to be the sideways movement that's going to be an issue.
"If you try and keep wicket over here, in these conditions that are very, very physically demanding, half-injured or with a slight injury, you're going to under-perform. You're not just going to let yourself down; you're going to let the team down as well."
Prior knows all too well the dangers of trying to play while injured. In the final matches of his Test career, he attempted to play through an Achilles problem that not only compromised his performance, but worsened the injury and hastened his retirement.
"I've learned from experience and unfortunately I couldn't come back from it," Prior said. "There is the bravado of 'Oh, I'm playing for my country, they're going to have to wheel me off'.
"But it doesn't get you very far, quite frankly. You'd rather go away, give yourself that extra week to come back fully fit so that you can perform at 100%. Not only for yourself, but for your team."
But Prior, who witnessed Foakes equal his record as he is in Galle as part of the Talksport 2 commentary team, did suggest that "it would be harsh" to leave out Bairstow if he is fully fit.
"We're very quick to forget Jonny has been one of England's standout performers over the last couple of years," Prior said. "He's a phenomenal talent and I don't think we want to look a gift horse in the mouth. Jonny, fully fit, would have played this Test match, probably would have performed well, done well with the gloves and scored runs and we wouldn't be having this conversation. I think it would be harsh not to pick him.
"You want to remember what a good player Jonny Bairstow is. If he is fully fit, then he should come back in to the team. Whether he keeps wicket, that's a whole other conversation. Who knows? That will be based on the balance of the team.
"The selectors have given themselves a nightmare by bringing Foakes over here in the first place. How are we going to play, potentially, Bairstow, [Jos] Buttler and Foakes in the next Test? I haven't worked it out yet. The only thing I can come up with is if Ben Stokes then moves up to three, you have Joe Root at four and Bairstow, Buttler, Foakes, Moeen Ali, Sam Curran. That's quite a batting line-up.
"You've got to pick the team that's going to win you a Test match on any given day. That's how you have to go about your selection, otherwise you can get too emotional about it. If it's deemed that actually Ben Foakes isn't in that XI that's going to win in Kandy then you have to make that tough call. It is going to be a selectors' nightmare."