Lions flanker Lewis Moody faces a race against time to be fit for first Test contention against New Zealand next week.
The Leicester forward has withdrawn from his place on the bench for Wednesday's clash against Wellington, when he will be replaced by his England colleague Richard Hill.
The Lions confirmed Moody had suffered an injury to his left knee in training, but the apparent seriousness was not revealed until coach Gareth Jenkins spoke to the media in Wellington on Tuesday.
Jenkins revealed that Moody is "out of the selection process" for next Saturday's game against Otago in Dunedin, and that will seriously hamper his Test prospects, given the Lions boss Sir Clive Woodward is likely to have finalised his first choice line-up by early next week.
Moody has not travelled to Wellington, remaining behind at the squad's Christchurch base for further tests.
Three players - Lawrence Dallaglio, Malcolm O'Kelly and Simon Taylor - have already been ruled out of the tour because of injuries.
The possible loss of Moody would be a huge blow, given his versatility at blindside and openside flanker, but it would appear the signs are not good.
Prop Andrew Sheridan, meanwhile, is battling to overcome an ankle injury sustained against the New Zealand Maori last Saturday, raising doubts about his prospects of being fit to face Otago. Like Moody, Sheridan is a serious candidate for the Lions' Test 22.
The British and Irish Lions team to play Wellington on Wednesday is:
J Lewsey (Wasps and England); J Robinson (Sale and England), B O'Driscoll (Leinster and Ireland, capt), G Henson (Ospreys and Wales), G Thomas (Toulouse and Wales); J Wilkinson (Newcastle and England), D Peel (Lanelli and Wales); G Jenkins (Cardiff and Wales), S Byrne (Leinster and Ireland), J White (Leicester and England), D Grewcock (Bath and England), B Kay (Leicester and England), S Easterby (Llanelli and Ireland), N Back (Leicester and England), M Corry (Leicester and England).
Replacements: G Bulloch (Leeds and Scotland), M Stevens (Bath and England), P O'Connell (Munster and Ireland), R Hill (Saracens and England), C Cusiter (Borders and Scotland), S Jones (Clermont Auvergne and Wales), S Horgan (Leinster and Ireland)
Billy Twelvetrees spoke to Gloucester Rugby TV after contributing fifteen points for the team at Twickenham. Despite the defeat, Twelvetrees praised the effort shown by his team, but rued silly errors that gifted London Wasps easy points.
Director of Rugby Nigel Davies was quickly able to identify a couple of key areas where Gloucester weren't quite good enough on the day, when he spoke to the media following defeat in The Stinger at Twickenham.
Huia Edmonds spoke to Gloucester Rugby TV this week ahead of Gloucester's clash with London Wasps in #TheStinger. The Australian hooker is yet to play at Twickenham and is excited at the prospect and putting things right on the pitch.
The bitter disappointment of losing against London Wasps in the Amlin Challenge Cup less than a fortnight ago, will give Gloucester ample motivation against the same opponent at Twickenham on Saturday says Director of Rugby Nigel Davies.
Billy Twelvetrees spoke to Gloucester Rugby TV following the 17-18 loss to Bath Rugby in Round Nineteen of Aviva Premiership Rugby. The Gloucester skipper said he was proud of the desire shown by his team at the end of a tough afternoon.
Nigel Davies spoke to Gloucester Rugby TV following the gutting 17-18 reverse to Bath on Saturday afternoon. The Director of Rugby expressed his pride at the efforts from his players and thanked the supporters for their incredible backing.
Nick Wood spoke to Gloucester Rugby TV this week ahead of Saturday's West Country derby clash with Bath Rugby. The front rower called on the squad to make a strong start and get the Kingsholm crowd behind them
Director of Rugby Nigel Davies admits that it's been a tough week at Gloucester Rugby following defeat at London Wasps last weekend, but that he's looking for his team to rise to the occasion for the huge game at home to Bath Rugby on Saturday.
Gloucester Rugby's trip to Twickenham ended in a 38-30 defeat to London Wasps in the sunshine. The hosts ran in 5 tries to Gloucester's three on a tough afternoon that despite plenty of promise saw Gloucester let down by errors.