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."

Between April and October 103 liner visits are scheduled to Guernsey, Alderney, Sark and Herm.
In 2011 there were 91 scheduled visits, with 29 being cancelled due to bad weather and itinerary changes.
Capt Peter Gill, Guernsey's harbour master, said: "It was a very poor year in weather terms and affected virtually every aspect of our activities."
He said: "It wasn't just the cruise liners, visiting yachts as well were significantly down on previous years, in fact last year was the worst since 1987."
Investigations into plans for a cruise liner berth off Guernsey, estimated to cost between Â£60m and Â£80m, are due to form part of the harbour master plan, which is due to be released this year.
Currently passengers are ferried between the cruise liners and Guernsey on tenders carried by the ships.
Capt Gill said: "In terms of a destination port in the UK, Guernsey is the most visited, it is the most popular... the cruise liner operators have made it quite clear to us they are very keen to come here."

Routine monitoring by Argyll and Bute Council discovered raised levels of algal toxins in Loch Melfort and Seil Sound.
The naturally-occurring toxins were above the "legally-permitted levels for harvest".
Members of the public have been asked not to gather them.
The toxins accumulate in molluscs such as mussels, oysters, cockles and razor clams, and when levels breach statutory limits, harvesting of affected species is prohibited.
Elsewhere, raised levels of Escheria coli (E.coli) bacteria have been identified in Oitir Mhor Bay.
It follows the discovery of raised levels at Kerrera West, Loch Craignish, Kilfinichen Bay and Castle Stalker.
They were discovered by the council's environmental health team as part of their work to maintain the quality of shellfish.
Potential raised levels of E.coli were also found at Dunstaffnage, Kerrera East, Loch na Cille and Loch Riddon.
A council spokesman said: "Eating shellfish such as cockles, mussels, oysters and razor fish from affected areas can pose a risk to human health.
"Notices to warn the public and casual gatherers have been posted along the shore. Commercial shellfish harvesters in these areas have been contacted by the council and steps taken to postpone harvesting until bacterial levels subside.
"People are advised to avoid eating shellfish from these areas until further notice as a precaution. When levels subside, the warning notices will be removed."
Derby County boss Nigel Pearson says injury may force Jacob Butterfield and Marcus Olsson to miss Saturday's season opening game against Brighton.
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Almost 150,000 cruise ship passengers are scheduled to visit the Bailiwick of Guernsey during 2013.
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People have been warned not to eat shellfish in parts of Argyll and Bute after raised levels of toxins were found.