The younger of the two celebrated international siblings was highly impressive in his new role last week when the Edinburgh outfit swept aside city rivals Currie 58-0 at Myreside.
Today the 33-year-old Hastings has a further chance to show that the No 15 jersey worn by brother Gavin suits him equally well as the No 13 has in over a decade when Watsonians take on league leaders Stirling County at Bridgehaugh.
Ker said: "I think he could play full-back for Scotland. His experience alone would be invaluable to them - it just depends what they are looking for.
"There is no doubt he has still got as much enthusiasm as he had 10 years ago."
Whether that enthusiasm extends to making the switch permanent is unclear, however. As Ker admits, it was not something the 66-times capped centre readily agreed to.
"I think he would prefer to play centre, where he still sees himself higher up,"the coach said.
"He is playing at full-back for us through necessity at the moment, with Colin Begg injured and Andrew Drought having gone back to Wales for the holidays. But Scott being Scott will do it to the best of his ability."
Last year's runners-up may not be able to call on captain Grant McKelvey for a further eight weeks, after the hooker underwent a scan this week on the Achilles tendon problem that forced him out of Scotland's match against South Africa.Reuse content