Olympic champions Joanna Rowsell and Steven Burke have pulled out of the Great Britain team for this weekend's Track World Cup event in Glasgow.
Academy riders Elinor Barker and Joe Kelly will take their places in the squad.
Rowsell was recently hit by a virus and her absence breaks up her world and Olympic-winning combination with Laura Trott and Dani King with whom she had set six successive world records.
Barker is the world junior road time-trial champion and European junior individual pursuit champion, so she will be an excellent deputy at the Sir Chris Hoy Velodrome.
Burke's absence from the men's team pursuit squad means none of the four-man team which won Olympic gold in London will be riding in Glasgow.
British Cycling performance director Dave Brailsford said: "It's a fantastic opportunity for these two youngsters to step in and experience the GB competition environment at an elite level."
Ed Clancy, who won 4,000 metres team pursuit gold in London, will compete in the three-man, three-lap team sprint, which takes place on Friday's opening day of competition.
Clancy will fill the man three spot occupied by Sir Chris Hoy as the Scot combined with Philip Hindes and Jason Kenny to win gold in London.
Clancy told www.britishcycling.org.uk: "We are going into the unknown but what is the worst that could happen? I get dropped and ride for three laps on my own, I'll never do team sprint again and go back to the team pursuit.
"As much as I'd like to stay on there and do a good last lap and open up another doorway, another option for someone to look at in the future, I wasn't a team sprinter before this little journey, there's no worst case scenarios really.
"It's going to be quite interesting to see whether I can match those boys for acceleration when they get going."