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The Leicester forward has withdrawn from his place on the bench for Wednesday's clash against Wellington, when he will be replaced by his England colleague Richard Hill.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)
Speaking to the local media this week, David Humphreys insisted that Gloucester are looking forward to kicking off the new European Rugby Challenge Cup against Brive on Thursday evening, although an unfamiliar opponent and a five day turnaround will pose a challenge.
Director of Rugby David Humphreys felt that his Gloucester side put themselves in a position to put Saracens under real pressure at Allianz Park on Saturday, praising his team's commitment and defence, while admitting that a lack of accuracy hit their chances in the second half.
Speaking to the local media at Allianz Park, Tom Savage was disappointed after the defeat at Saracens, but claimed Gloucester did plenty of good things and could've taken more than a losing bonus point.
In case you missed it, there was plenty of activity on the official Gloucester Rugby website following the 55-0 European Rugby Challenge Cup win over CA Brive, including a number of post match video interviews.
The Cherry and Whites ran in seven tries in beating CA Brive 55-0 on Thursday night. An emphatic second half performance saw the hosts run in five tries to get the European campaign off to a flying start.