Davis sustained the injury at the Team GB preparation camp in Belo Horizonte. McConnochie, one of two travelling reserves, steps in to the 12-man-squad while Charlie Hayter will fly to Rio to provide replacement cover alongside Luke Treharne.
''It has been a tough year for Alex for a number of reasons and to have this setback is incredibly disappointing for him,'' said coach Simon Amor.
''But he is one of the most mentally resilient people I know. He will come back from this and I'm confident he will have a strong career for England Sevens and with Team GB at the Olympics in four years' time.
''It has been an amazing 12 months for Ruaridh who has played in all but one of the tournaments in the World Rugby Sevens Series this year. He can cover a number of positions and is on excellent form.''
The GB team, made up of players from the usually-separate England, Scotland and Wales, start their campaign against Kenya on Aug. 9 as Sevens makes its first appearance at the Olympics.
(Editing by:)
