Wolfsburg suffer keeper injury blow
The 24-year-old Dane only recently joined the club, on a season's loan from Scottish Premier League outfit Rangers, but is now unavailable for the start of the new Bundesliga campaign.
"I have not trained with my teammates for one week, but I expect to be ready to take up the competition with Claus Reitmeier within a couple of weeks," said Christiansen to Ekstra Bladet.
Meanwhile, fellow countrymen Kim Madsen and Thomas Rytter are expected to be ready to face Schalke in the opening match of the season.
"We have practiced hard and therefore we have informed the coach that we are a little tired, but I expect Thomas (Rytter) and I to play against Schalke," said Madsen.