Winfield is entering the final year of his contract. But coach Brad Childress says the cornerback is out because he is attending the funeral of a close friend's mother.
Winfield was the only player on the 85-man roster who was not on the field when the minicamp opened on Friday. He is coming off his first Pro Bowl appearance and will turn 32 in June.
His agent, Ashanti Webb, did not immediately return a phone message from The Associated Press.
Webb said earlier this month that contract negotiations had reached an impasse, but Childress has said multiple times that the team would like to get a deal done.