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The Leicester forward has withdrawn from his place on the bench for Wednesday's clash against Wellington, when he will be replaced by his England colleague Richard Hill.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)
Previewing Friday evening's local derby at Bristol, Interim Head Coach Jonny Bell told the local media that Gloucester's preparations have gone well and that the whole squad is united in trying to finish the season on a high.
Speaking to GRTV this week, Acting Head Coach Jonny Bell spoke of his pleasure in the efforts and intensity in training from the squad after a tricky few weeks. The team were preparing for big games with Bristol and Cardiff in coming weeks.
Willi Heinz was understandably and visibly disappointed when he spoke to GRTV after the 27-30 home defeat to Harlequins, apologising to the home support as the game slipped away after seemingly having the game under control.
Speaking to the local media this week, Scottish centre Matt Scott spoke of the squad's determination to put in a big home performance against Harlequins, with vital points up for grabs in the hunt for a Top Six spot this Saturday (KO 3pm)
Looking ahead to Saturday's Aviva Premiership fixture at home to Harlequins (kick off 3pm), Head Coach Laurie Fisher told the local media that Gloucester will need to be on top of their game in a match which has big implications in terms of top six ambitions.
A big few days for the Gloucester-Hartpury Women side. First came the news that the team will compete in Women's Super Rugby next season, and on Saturday the team will play Worcester Ladies IIs at Kingsholm. Centre Hannah Jones and wing Michelle Ruddock spoke to GRTV this week to reflect on events.
Missing so many starters, and up against a team fighting for their Premiership existence, Gloucester did what had to be done at Ashton Gate on Friday evening battling their way to a 32-14 Aviva Premiership win over Bristol Rugby.