Swiss bobsledder Sandro Michel was in a stable condition in hospital on Wednesday after a heavy training crash on the German sliding track of Altenburg the previous day.
Michel was part of Michael Vogt's four-man team and fell out of the bob when the bob tipped over. He was then run over by the sled which slid back from the finish area.
The world governing body IBSF said that Michel was flown to hospital in Dresden and underwent surgery on chest, hip and thigh injuries.
The Swiss team said that Vogt suffered severe concussion and bruises, and the two other team members, Dominik Hufschmid and Andreas Haas, sustained minor injuries.
Vogt and Michel finished fourth in the two-man event at the 2022 Olympics and got bronze at last year's world championships.
The German team with pilot Johannes Lochner crashed at the same section, with officials saying two-man world champion Lochner is being examined for potential cervical vertebrae injuries.
An investigation into the accidents has been launched.
Altenberg is hosting the last World Cup events ahead of the world championships in Winterberg, Germany, which start next week.