Captain Alun Wyn Jones will not travel to South Africa with the British and Irish Lions after dislocating his shoulder during Saturday’s warm-up game against Japan.
Warren Gatland’s side leave on Sunday and Jones will return to Wales, with a replacement yet to be decided.
Gatland said the “very best case scenario” was that the four-time Lion would be fit for the first Test against the Springboks on 24 July.
“He’s going to be gutted,” he added.
“I’ve spoken to the physios, they’ve spoken to Alun Wyn, he understands the very best scenario is he may get back for the Tests.
“We need to call someone and get them [Covid-19] tested and hopefully get them on the flight tomorrow.
“We’re discussing names with the other coaches.”
Gatland said that flanker Justin Tipuric could yet be ruled out of the tour as well after suffering a shoulder injury.
“He got a sting in the shoulder so we’re just going to check to make sure there’s no nerve damage,” the former Wales head coach said.
“If there was that could rule him out but at the moment we’re pretty confident he’s going to be ok.”
‘No one is in shock’ – Gatland
Jones left the field after seven minutes in the four-try win against Japan following a hit by Japan’s James Moore in a ruck.
The 35-year-old was set for his first Lions tour captaincy having featured in the last nine Tests the side has played.
Gatland said Jones was yet to undergo a scan to determine the extent of the damage and added that he was uncertain whether a new tour captain would be named.
“No one is in shock,” the New Zealander continued.
“If you are in shock, it reflects back into the whole squad. We understand that things have got to be fluid.
“We’ve got to make the right decisions as quickly as we possibly can and in the calmest way we possibly can.”
‘It is a huge loss’ – Biggar
The Lions’ current second row options include Tadhg Beirne, Iain Henderson, Jonny Hill, Maro Itoje and Courtney Lawes.
Itoje was included among the pre-tour contenders for captaincy, as was England skipper Owen Farrell and Scotland’s Stuart Hogg.
Wales team-mate Dan Biggar said Jones was “pretty down in the changing room”, adding that his absence would be a “huge loss”.
“You’ve only got to look at his record and experience,” Biggar said.
“He’s the go-to guy. Things move so quickly on these tours. You’ve just got to put it to one side now and look at the group we’ve got.”