text: Butterfield has a thigh injury while Olsson suffered a concussion in their 1-0 pre-season win at Sheffield United.
  "With any head injury you err on the side of caution," Pearson said.
  "We could push Jacob back quickly but I don't see the point in putting him into a situation where the potential for injuring him further is there."
  Pearson's Rams have six games in 20 days during August, but have few injury concerns other than Butterfield and Olsson.
  "It's a long season we've got to make sure any teething problems with players are managed sensibly because I'd like a fully-fit squad to choose from every week," Pearson told BBC Radio Derby.
  "I'm not going to have that but that's what the aim is. We want to keep the players in good condition and available."
  Derby drew with Brighton in both league meetings last season, but the Rams boss is happy with the level of preparation going into the new campaign.
  "Match days are a different entity to the rest of the week.," he said.
  "We always do as much as we can whether it's enough at any given time remains to be seen."
target: Derby County boss Nigel Pearson says injury may force Jacob Butterfield and Marcus Olsson to miss Saturday's season opening game against Brighton.