Harlequins and England have been hit by a blow after back-row Jack Clifford dislocated his shoulder in his club side's 42-26 win over Sale.
Clifford was forced from the field in the Premiership victory and had his right arm in a sling after a collision at a breakdown at the Stoop.
Director of rugby John Kingston admits the injury doesn't look good for the 24-year-old, who was recently called into the England squad.
"It looks like Jack has dislocated his shoulder. It's frustrating for him. It's too early to say how long he'll be out for," boss Kingston said.
"To give an insight on where we are injury wise, last night (Thursday) we had a training session here under lights and we actually had five players in doubt.
"Three of them missed and two of them got in and Jack was one of those. He had a sore biceps and pec on the left side, so he had strength tablets to get out on the pitch in the first place.
"It was disappointing because he played ever so well while he was on the pitch."