Henry Paul will miss the remainder of the season after Gloucester's medical team confirmed he has damaged the medial ligament in his knee.
The England international injured his knee playing for England Sevens at the World Cup in Hong Kong 10 days ago and was ruled out of last Saturday's win over London Irish.
Paul is set to be out for between six and eight weeks and will be unavailable for Gloucester's final three Zurich Premiership games, and any play-off matches.
Commenting on www.gloucesterrugbyclub.com Melville said: "It's a set-back but in some ways sums up our season. We have just had so many people injured at crucial periods, but you only have to look around the Premiership to see that other clubs are in a similar situation."
Commenting on www.gloucesterrugbyclub.com Paul added: "It's a big disappointment. I'm concentrating on getting back to full fitness, and will be right behind the rest of the team as we push for the top three slot in the Premiership and next season's Heineken Cup."
Paul, who has missed only a handful of games in four seasons with Gloucester, will see a specialist next week who will assess whether an operation is required.
Despite the injury, Nigel Melville's fly-half options could be boosted for Gloucester's next Premiership game at home to Leeds Tykes on Saturday 9 April with the return of Duncan McRae.
The Aussie stand-off has had an injury hit season, with his most recent knee injury ruling him out since the defeat away at Quins at the beginning of February.
As well as McRae's possible return, 22 year-old Brad Davies, who played the full 80 minutes at number 10 for Gloucester in the 13-12 win over London Irish on Saturday, was in commanding form for Gloucester against the Exiles at the weekend.
Gloucester will field a reshuffled side against the Ospreys in the LV= Cup this weekend, but Backs & Attack Coach Nick Walshe stressed that it's a great opportunity for everyone on duty on Saturday and that maintaining the recent winning run is very important.
Skipper Billy Twelvetrees told GRTV after the win in Brive that the game could have been a tough one to get up for, but that his Gloucester team mates did themselves proud on the night and got a big result.
Reflecting on the 31-20 victory in Brive on Thursday evening, Director of Rugby David Humphreys said that clinching a home European Rugby Challenge Cup quarter-final was the overall aim and duly achieved.
Gloucester may have already clinched a home European Rugby Challenge Cup quarter-final, but Director of Rugby David Humphreys wants his side to finish the pool stages on a winning note in Brive on Thursday evening.
Speaking after Saturday's win, James Hudson was happy to record a bonus-point win against a hugely physical Oyonnax side as Gloucester secured their passage into the European Rugby Challenge Cup Quarter Finals
Billy Burns was a try scorer on his first European start for Gloucester and, speaking after the game, admitted that it was good to get the five points although there are still things to work on before the trip to Brive.
Gloucester Rugby have added to their front row strength in depth for next season with the signings of Paul Doran-Jones, Paddy McAllister and Nicky Thomas from Harlequins, Aurillac and the Ospreys respectively.