Wales are hopeful Dan Biggar will be fit to face England in the Six Nations on Saturday and Liam Williams is set to make his first appearance of the tournament.
Biggar suffered a knee injury during Northampton Saints' Premiership defeat to Saracens last weekend.
The fly-half is on course to play at Twickenham, though, as the defending champions attempt to stop the rot after back-to-back defeats at the hands of Ireland and France.
Former Wales captain Sam Warburton, working as a breakdown specialist in Wayne Pivac's set-up, said of Biggar: "He's looking good.
"The initial signs are positive. He doesn't need a scan. It puts our team selection on hold for a while because we have to wait to see how he turns up tomorrow.
"He's going to train and do stuff with the physios. But everyday so far, the feedback from the physios has been good, he's had a really good response to the stages of physio.
"He's ticking all the boxes he needs to. He's on a good course so, hopefully, with no hiccups, we'll have some good news. There are no guarantees but we're confident at this stage.
"There's a hurdle every day, the training becomes gradually more intense and will climax towards the end of the week. So if he can pass that, then all good. We're taking it day by day but the first two days have been all good.
"I don't know to be honest but I think we'll have a conclusive answer by Friday morning."
Williams has not played since suffering an ankle injury at the Rugby World Cup, but the full-back is poised to face the Red Rose.
Warburton said: "He’s back in full training. He will hopefully be in contention to start.
"This is the sort of cauldron he would love to be thrown into. It will be great to have some big game players back."
Wing Hallam Amos will definitely not feature after he was ruled out for the rest of the tournament with a knee injury.