The Dane suffered a knee ligament injury during Celtic’s qualifying win over Rosenborg on Wednesday and faces about six weeks out, meaning he will miss both play-off legs against Astana of Kazakhstan later this month.
Manager Brendan Rodgers was already without Dedryck Boyata until September with a knee injury and played midfielder Nir Bitton beside Jozo Simunovic in Norway after Sviatchenko went off.
Speaking at his pre-match media conference ahead of the Ladbrokes Premiership opener against Hearts, Rodgers said: “We’ve just had his results so he will probably be up to about six weeks, which is disappointing.
“It could have been worse but we will take it at six weeks, not probably back until September.”
Sviatchenko had missed the first leg with a groin injury and returned to training on the eve of the 1-0 away victory.