Jamie Roberts is hopeful he will be cleared to face Samoa in Wales' second autumn international on Friday night.
Roberts and former skipper Ryan Jones are racing to be fit for the Millennium Stadium clash with the former needing to pass a battery of tests on a concussion he suffered in last weekend's defeat by Argentina.
Jones missed that match with a shoulder problem but he is ready to return to action and start at flanker against a Samoa team that caused them plenty of problems at the World Cup in New Zealand last year.
Both players being available would be music to coach Rob Howley's ears as he deals with an injury crisis that includes Alun-Wyn Jones, Josh Turnbull, Adam Jones and Dan Lydiate.
"I hope to play against Samoa, fingers crossed, but I have to go through the protocols," said Roberts. "I did not suffer any memory loss and the medics have taken good care of me.
"I tackle pretty upright, and it was probably my fault because it was pretty poor tackle technique. His (Gonzalo Tiesi's) head caught me right on the sweet spot on the jaw. I was knocked out before I hit the floor.
"I was a little bit too disorientated to go back on and play. The medics felt I was not quite right.
"But after the game I perked up and felt okay. This week is just about going through a strict protocol where you are tested rigorously."
Jones said: "By pushing it back another five days when the squad was due to come home, it would probably have ruled me out of the game this week.
"In this day and age you are almost fortunate to finish a game without a bump or a bang. It only takes one bang as well. Jamie's was pretty innocuous. It was a one-on-one which became a clash of heads, and Alun-Wyn was another one - he has had a bump and has fallen awkwardly. That's the nature of it now."