“He had a little bit of pain after the game,” Horne said. “He’s such a tough player – he doesn’t really complain about anything – but he had a bit of swelling in his hand.
“He went for a scan and an x-ray and he’s actually got a fracture.”
Scotland’s defeat by Fiji dented their hopes of improving their world ranking in order to be among the top seeds at the World Cup draw in December.
However, Horne said head coach Gregor Townsend did not have to be persuaded to part with Graham.
“Gregor’s a massive supporter of the Lions,” he said. “If they’d needed them now, he’d have been all for them going away.
“But, then, getting another game with us, I think is part of the Lions’ plan. They were happy for them to play this weekend and I think the fact that we’re playing on a Friday definitely helps.
“Friday night to the Wednesday isn’t as bad as a Saturday to Wednesday. So I’m sure Gregor will be quite willing to support any plan that Andy [Farrell] and the Lions have.
“If it means limiting a little bit of game time or whatever then I’m sure that’ll be the case.”
Scotland, who initially lost eight players to the Lions, have no plans to call in any late replacements of their own.
“By the time anyone gets out of here, it’ll take them a few days with the jet lag and stuff – it’s a tough old travel,” Horne added. “We’re pretty well covered, to be honest.
“We’ve got adequate cover across the backs. Training might be a little bit hampered, but I’m sure we’ll be fine.”
