
Swedish coach Lars Labergack said "Fredrik will get more treatment and we will decide later if he can play" on Wednesday.
Ljungberg of Premier League side West Ham United told reporters that his calf injury felt better and he had done some rushing exercises during the practice Tuesday.
Sweden host Northern Ireland and a win would clinch a spot in the 2008 finals.
Lagerback is also keeping tabs on defenders Mikael Nilsson, Olof Mellberg and midfielder Tobias Linderoth.
If Nilsson of Greek side Panathinaikos is unable to play, he will likely be replaced by Mattias Concha of Vfl Bochum, who was lauded for his performance against Liechtenstein last Saturday.
Sweden and Spain top group F on 22 points, followed by Northern Ireland on 16.