Coach Andy Flower revealed Prior, unable to keep wicket after hurting his calf while batting on the final day of the drawn fixture at the Bellerive Oval, will have a scan on his lower left leg.
England are hoping Prior - a pivotal mainstay in their last three successful Ashes series, and Alastair Cook's vice-captain too - will still be fit for the first Test in Brisbane on November 21.
But Flower admits the tourists cannot be confident at this stage.
"He is a concern. He's tweaked something in his calf," he said.
"We're not sure of the extent of the injury as yet ... he will obviously need a scan."
Speaking after England had declared on 430 for seven and then managed to give their bowlers 31 overdue overs, following consecutive washouts on days two and three, Flower appeared heartened that Prior had little time to exacerbate the injury - because he was out very soon after first feeling discomfort.
Prior appeared to hurt himself scampering a quick single in company with Joe Root (58no), who later found himself pressed into service as England's emergency wicketkeeper.
Flower said: "He didn't make it much worse - he was off soon after he tweaked it.
"As soon as we know more about it, we'll tell you. He'll go for a scan pretty much as soon as possible."
As England depart for Sydney on Sunday for their final warm-up match, any optimism can be no more than cautious.
"I don't think it's anything too serious, and shouldn't keep him out of the first Test," Flower added.
"But let's just scan it, and then we can give some more information. Just from what I've seen, I would imagine he'd be okay for that first Test.
"But I hope I'm not speaking out of turn there.
"He's moving around okay ... I don't think it's linked to the Achilles problem [he has had in the past]."
As for whether Prior could yet even play against an Australian Invitational XI next week, the coach said: "We don't know yet. It's possible.
"His experience is very valuable to us. However, if he's injured and unavailable, (Jonny) Bairstow will step in.
"He is a very good young cricketer, and will bring his own qualities to the England side."
Bairstow could not step into the role in Hobart, because playing conditions did not permit it.
Root therefore did, and did not look out of place - taking a catch and missing little as the hosts closed out the stalemate on 119 for three.
"The rules of first-class cricket are quite black-and-white and don't allow a substitute fielder to take the field as wicketkeeper," said Flower.
"So Jonny couldn't do it. Root took over, and I thought he did a really good job.
"He looked a natural. He takes on any challenge with a smile on his face, and also no mean skill.
"It's not an easy thing to do at all, and he handled himself really well out there.
"I was surprised. But he's a natural ball-player, and I think he had a bit of fun as well."
Flower also inevitably found himself reacting both to Shane Warne's renewed criticism of Cook, whose captaincy Australia's record-breaking former leg-spinner rates "boring" and "negative" - as well as the leaking of an 82-page document specifying England's refined nutritional requirements at this winter's Ashes venues.
"People are going to criticise Alastair; they'll criticise me, our selectors, our players," he said.
"That's part of the job obviously, and I think everyone realises that. We've got enough on our plates ... to worry about that."
As for the publication of an exhaustive menu including a raft of exotic health foods, Flower said: "I think in most areas we want to be well-prepared, and I would imagine most sporting organisations have an idea of the type of nutrition they want to make available to their sportspeople.
"The English cricket board is no different in that regard."
England will be more concerned with fine-tuning their preparation and selection for the first Test, a task which has become no easier after an awkward few days in Tasmania.
Frontline bowlers Graeme Swann and Stuart Broad have only 16 overs under their belts since leaving home, while Kevin Pietersen could make only eight in his first innings on tour.
Flower said: "Our policy is to announce the team at the toss - and we're still 12 days away from that.
"We have got a clear idea, yes, and more than likely the top six - and possibly the top seven, if Matt Prior is okay to play the game - will be the same top six or seven we use in Brisbane."
Rain in Hobart was beyond even Flower's control, and he said: "There's nothing you can do about bad weather.
"It's a pity - it is what it is - but I think we made the most of what time we've been allowed in the middle.
"Whatever happens - even if there are weather problems in Sydney - we will make sure we are ready for that first day in Brisbane."