A Providence, Rhode Island native and clearly the greatest center and most talented frontcourt player in PC history, Barnes was the center of the Friar offense and team MVP in 1973 and 1974. The 1974 NCAA national rebounding champion, he was a consensus First Team All-America, Eastern Player of the Year and Most Valuable Player in both the Aloha Classic and East-West All-Star games. Barnes was the second pick in the 1974 draft who later became the Rookie of the Year in the ABA where he played for two seasons. He moved on to the NBA for four seasons. Barnes was named to the ECAC All-Decade team for the 1970's. He still holds Providence game, season and career records for rebounds and blocks.
Barnes played in the American Basketball Association from 1974 to 1976 and in the National Basketball Association from 1976 to 1980. He had his greatest success in the ABA, where he starred for the Spirits of St. Louis and was named Rookie of the Year for the 1974-75 season. He also shares the ABA record for most two-point field goals in a game, with 27. In 2005, the ABA 2000, the second incarnation of the ABA, named one of their divisions after him.
In 1973, he was the first player to score 10 times on 10 field goal attempts in the NCAA playoffs, and remains tied for second behind Kenny Walker, who went 11-for-11 in 1986.
In March 2008, PC retired his jersey, honoring him along with Ernie DiGregorio and Jimmy Walker.