London Wasps and England loose head prop Tim Payne has been called into the British & Irish Lions' squad for the remainder of the tour.
Tour manager Gerald Davies and head coach Ian McGeechan announced the news on Sunday, a day after the narrow defeat to South Africa in the opening Test.
McGeechan explained: "Tim Payne has been called up to provide essential cover for the front row as Andrew Sheridan is responding slowly to treatment for a sore back following the Southern Kings match.
"We simply can't go into this week without sufficient cover at loose head prop as we play the Emerging Springboks and the Springboks in the space of five days.
"Tim Payne will arrive match fit having played in all three of England's recent international matches against the Barbarians and Argentina.
"We are still hopeful that Andrew Sheridan will respond to the medical regime he is currently undergoing."