Barker, who played 304 times for the club, passed away peacefully at Lindsey Lodge Hospice this week after a short illness.
His most famous moment for the club came in a famous FA Cup fourth round win over Sheffield Wednesday at Hillsborough, when he gave himself severe concussion while scoring with a diving header.
While his team-mates went on to win the match, he was rushed to hospital.
He left the club in 1975 to join Yorkshire outfit Scarborough.