"We ratified," CSO bassoonist William Buchman, a member of the negotiating committee, told the newspaper.
Without offering many details about the pact, he said, "The musicians will be contributing significantly more toward health care costs."
CSO Association President Deborah Rutter told the Tribune the board won't ratify the contract until it meets sometime in the next few days.
"We don't have a ratified contract yet," she said. "We're working on getting a board meeting scheduled, and hopefully it will be very soon."
A weekend performance at Symphony Center was canceled due to the strike, which started after 11 negotiating sessions between the association and musicians failed to produce a contract satisfactory to both parties.