Tom James has been named ahead of Alex Partridge as the final member of the Great Britain men's four at the start of the Olympic season.
James rejoins fellow Beijing gold medallists Pete Reed and Andrew Triggs Hodge, along with Alex Gregory, for the imminent World Cup season.
Reed, Hodge, James and Steve Williams won Olympic gold in Beijing in 2008.
Partridge will now row in the men's eight, with the World Cup squad likely to remain unchanged for the Olympics.
"I'm looking forward to being in the four in Belgrade," said James, currently training with the British squad in Italy. "After a long and sometimes difficult winter of training, it will be good to get racing."
Partridge added: "I love the eight, I love racing in it and I'm very excited to be with such a strong group of guys. At the end of the day I want to be in a place in the team where I know that I can do everything I can to be the best I can be when the Games come round."
The World Cup season gets under way in Belgrade on 4-6 May, before moving on to Lucerne later that month and Munich in June. The Olympic squad will be named on 6 June.
"The objective has always been to have a strong strategy across the squad and to produce more than one top boat," said men's chief coach, Jurgen Grobler. "There are no winners and losers today."
GB Rowing has also confirmed that Phelan Hill, on leave from his role as a special advisor at HM Treasury, has seen off competition from Rowley Douglas and Acer Nethercott and will cox the men's eight in Belgrade.
The men's quadruple scull will comprise of Matt Wells, Stephen Rowbotham, Charles Cousins and Tom Solesbury, with Marcus Bateman contesting the single scull in Serbia.