The injury, which occurred in the sixth minute of the Test in Sydney, will rule him out of the rest of the tour.
"We have been in touch with Murrayfield about the hooker situation," said Scotland team manager Arthur Hastie, who named the two players being sought as McKelvey and Scott.
The tourists face Queensland at Ballymore in Brisbane tomorrow, and coach Jim Telfer warned: "Queensland will be wanting to win. They will be very tough opposition.
"But the team we have picked is capable of winning. I thought last week that we let the Australian Barbarians off the hook."
The Scots have selected Test wing Derrick Lee at full-back in preference to Hugh Gilmour and have given David Officer a run at inside centre in partnership with the fast improving Jamie Mayer.