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The Leicester forward has withdrawn from his place on the bench for Wednesday's clash against Wellington, when he will be replaced by his England colleague Richard Hill.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 after the 37-8 European Rugby Challenge Cup win over Benetton Treviso, James Hook admitted that the Italian side made things tough for Gloucester at times but that the Cherry and Whites are happy to take the bonus point win and turn their focus to Northampton next week.
Speaking to GRTV after the game, Backs Coach Tim Taylor was happy with the squad as they cruised to victory over Treviso. The result wasn't in doubt, but the Cherry and Whites laboured to secure a crucial try bonus point.
Speaking to the local media this week, Gloucester Rugby centre Matt Scott is excited to take the field again as the Cherry and Whites look to build on the win in Bayonne when Treviso come to Kingsholm this Saturday.
Defence Coach Jonny Bell admitted this week that the European Rugby Challenge Cup victory in Bayonne was a welcome one, stressed that Benetton Treviso will pose a tough test on Saturday at Kingsholm but that Gloucester are determined to deliver in front of their own fans.
Motu Matu'u is looking to make up for lost time this week as the Cherry and Whites head to Basque Country to take on Bayonne in the European Rugby Challenge Cup opener. The Samoan hooker made his first appearance in the jersey last weekend, and is hoping to contribute to the team this weekend.
Gloucester's attentions turn to Europe this weekend as they travel to Bayonne for their opening fixture of this season's European Rugby Challenge Cup. Forwards Coach Trevor Woodman told GRTV that the Cherry and Whites will be aiming to top their pool as they've done for the past two seasons, but is well aware of how tough it is to win in France.
Although understandably disappointed at seeing victory slip away at the last minute, Ben Morgan said after the game at Exeter that there were plenty of positives that Gloucester could take from the game.
Gloucester made it two wins from two outings in this season's European Rugby Challenge Cup as they outplayed Benetton Treviso at Kingsholm to win by 37 points to 8, the bonus point try coming with the final play of the game.