Scarlets coach Nigel Davies was left fretting over Stephen Jones' fitness after the Wales fly-half limped off in the first half of the Welsh region's Heineken Cup bonus-point win over Treviso at Parc y Scarlets.
Jones, 33 this week, came off after 18 minutes of the 35-27 success after suffering a blow to his left knee.
"It will take 24 to 48 hours to have an accurate assessment. It's probably a tweak to the ligaments but we don't really know," said Davies.
"In the next couple of days we'll have a clear assessment. He's walking around, so that's a good sign.
"We will have it scanned after the swelling has gone down."
Davies said he was not satisfied with his side's performance despite scoring four tries to Treviso's three.
"They are a quality side. We know only too well about that because we have played them in the Magners League," he said.
"If you give them an opportunity they are dangerous and we are disappointed today with our game without the ball.
"When we did look after the ball we scored tries. It would have been nice to have finished the match off at half-time . We blew some great opportunities and overall we are disappointed with our performance, but having said that we know we can get better.
"It was imperative we won and a bonus point was important in the group we are in. We set out what we wanted to achieve but we also realise our performance wasn't great."