Guangzhou have travelled to South Korea without midfielders Elkeson and Rene Junior, striker Alan and defender Kim Young-gwon.
"We have a lot of injuries as we don’t have the international players Elkeson, Rene, Kim and Alan, so it is not normal," Cannavaro told reporters in South Korea on Tuesday. "But I trust my team and even without these players, we can have a nice performance."
However, Cannavaro's hopes of notching up a vital away win will be boosted by the form of Brazilian midfielder Ricardo Goulart, who has scored eight goals in 10 appearances for the Chinese Super League club, including a hat-trick in the group stage of the tournament against the Western Sydney Wanderers.
Despite Goulart's red-hot form as of late, Cannavaro still expects his side to be pushed to their limits on Wednesday as Seongnam will be playing in front of their fans at the Tancheon Sports Complex.
Cannavaro is also wary of the trouble Seongnam's Brazilian forwards Ricardo Bueno and Jorge Jorginho can cause.
"Seongnam are tough, they are Korean, and everybody knows Korean football," the former Italy international said. "They are aggressive and the stadium is not big so we know they can put us under pressure.
"We know that we have two games and not just one and we know that we need to be clever and understand the qualification is not only down to one game.
"We know everything about them; I have seen the last four games. They work together, they have very good Brazilian players, and if they have reached this stage they have the quality."