But Davies - who has also starred at the World Rugby Under-20 Championship and Six Nations for the Wales Under-20 side - impressed in Biggar's absence and Tandy is confident the youngster has the ability to hold the fort again next season.
And the 35-year-old is urging the former IRB Junior Player of the Year to take his chance when GUINNESS PRO12 rugby returns in September.
"We have every confidence Sam will do a good job during the World Cup period," he told the South Wales Evening Post.
"He was outstanding last term when Dan was away. He showed real maturity and a nice mix to his game and he and Tom Habberfield were excellent in the match with Munster in March.
"For me, that opening 40 minutes that day was one of the big plusses of the campaign.
"It was such a young group, coming off the back of a draw against Leinster and defeats by Glasgow and Edinburgh, and we saw real development.
"Sam still has plenty to learn - he is only young - but he is a player with a big future and we are looking to him to step up to the plate during Dan's absence.
"I know he won't be found wanting."
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