Josh Navidi appears on course to give Wales a huge boost and be available for Saturday's Autumn Nations Cup clash against England.
The influential Cardiff Blues back-row forward has not played Test rugby so far this autumn.
He missed Wales' friendly against France and a delayed Six Nations appointment with Scotland last month – plus Nations Cup games against Ireland and Georgia – after he suffered concussion in late September.
But Navidi and back-row colleague Taulupe Faletau, who had a minor knee issue, are back in full training ahead of the Parc y Scarlets encounter.
Wales, meanwhile, are continuing to assess flanker Justin Tipuric, who suffered a head knock during the Georgia game three days ago.
Wales assistant coach Neil Jenkins said: "If Navs is right, he's a fantastic player.
"For me, he is a world-class player, the type of guy with minimal rugby that can step up and play Test match football. He is one we are keeping a close eye on, and we will have a look on Thursday.
"Tips is going through his protocols, as you normally would after a head injury.
"It was a pretty heavy knock on Saturday, but he seems pretty good, and we will see how he goes for the rest of the week."
Wales head coach Wayne Pivac is due to name his starting line-up on Thursday, but star centre Jonathan Davies is expected to miss out because of a knee problem.
Pivac's men face a Herculean task, meeting England after losing six of their last seven games.
In contrast, dominant England have reeled off six successive victories, including a Six Nations title-clinching win against Italy, before dismantling Ireland last weekend.
Such disparity in form and results led to former Wales captain Gwyn Jones claiming this week that Wales are currently "miles behind" England.
"Gwyn is entitled to his opinion, and I've no problem with that. You would say that, the way things have gone so far," Jenkins added.
"But, look, we are a certain type in Wales and we would like the think we're going to back ourselves on Saturday and we fancy our chances.
"We are up against the second-best side in the world at this moment in time, and this is a big challenge for us.
"We wouldn't see it as a shock in here (if Wales won), but I am sure the rest of the world would.
"England are very strong at this moment in time. Their defence is incredible, their work-rate is incredible, they have a big kicking game.
"So there are going to be a lot of things we will have to deal with on Saturday, and we will have to do it well, otherwise we will come unstuck.
"But Wales-England games throw up a lot of different things – they have done in the past – so I would like to think we will be more than ready on Saturday to match, and hopefully better, England in a lot of areas.
"We know it's going to be tough, and we understand what is in front of us. But if we can do what we can do and perform how we can perform, we have got more than a chance on Saturday.
"But we need to be right on the edge and right on the money to give ourselves a chance. It would be a huge boost to everyone here, that's for sure, and to the country, obviously.
"England will want to maintain and continue what they are doing, and we want to get on the right end of it and get on a winning run ourselves."
Ross Moriarty, meanwhile, has been released from the Wales squad due to an ankle injury, and had not featured in the Nations Cup.
