The team announced the diagnosis on its Twitter account Tuesday, a day after Okposo, 30, was sent home for follow-up medical tests. Okposo was hurt Friday, when he was felled by a punch in the face during a fight with New York's Tony DeAngelo in the third period of a 6-2 loss to the Rangers.
Okposo did not return to play against the Rangers, but he was cleared to travel with the Sabres to open their three-game trip at New Jersey on Sunday. He did not play against the Devils, and he returned to Buffalo while the Sabres traveled to Florida to play the Panthers on Tuesday night.
This is the latest in string of concussions for the 12th-year player.
He missed the final two weeks of the 2017-18 season and spent nearly a week in a hospital after suffering a concussion during what he called a routine hit in practice. The effects led to Okposo losing a considerable amount of weight and having difficulty sleeping.
He also missed three games last March after suffering a concussion following a collision with Ottawa's Bobby Ryan.