"We will get Jamie scanned on Sunday. The medics thought it might have been a hamstring, but he said he has never pulled a hamstring before, so he is not kind of sure. It is fingers crossed it might not be that," said head coach Warren Gatland.
The Lions have already had injury concerns in the past week over centres Brian O'Driscoll and Manu Tuilagi, while George North has been nursing a hamstring tweak - not what the coach needs or wants a week out from the first Test.
"Manu trained on Friday and his shoulder is still a bit sore. George's hamstring is still a bit tight and so we are still progressing with them with the medics," said Gatland.
"Our hope is that both of them will be in contention for next week."