Head Coach Dai Flanagan admits it will “touch and go” for Jared Rosser for Judgement Day after praising the ‘superb’ impact of the back this season.
Rosser, who is primarily a winger, slotted in at 13 alongside Max Clark in the 40-21 defeat to Ulster but is a doubt for Principality Stadium.
The 25-year-old suffered a knee injury in Belfast and Flanagan will give the former Wales Sevens flier as long as possible after hailing his performances and attitude this season.
“Jared has been superb for us and a pleasure to work with since I've arrived at the club,” said Flanagan.
“I came in with the mindset that Jared was a player who I would sign if I was at any other club.
“I am really pleased that we have managed to retain him because he is such an athlete but also such a leader in the group for a young man.”
One player who will miss the date in the capital with Scarlets is Wales prop Leon Brown as he undergoes a neck and shoulder scan after being forced off early at Ulster.
“Leon's neck and shoulder area is getting scanned to make sure it's nothing serious, but he won't turn it around for this weekend,” added Flanagan.
“Hopefully it's nothing serious. He is moving his neck fine, he is a little bit weak in his shoulder, but fingers crossed.”
Flanagan is set to have centre pair Steff Hughes and Sio Tomkinson back available for selection and has hinted at ‘subtle changes’ as some players prepare to leave the club.
“There will be changes, particularly on the bench given the opposition and then players with stuff to play for,” he said.
“Rugby is such a collision sport and an emotional sport that sometimes you need something to play for.”