[citation needed] He was named the starter at middle linebacker as a sophomore, but failed one course and had two D's, which forced the school to make him ineligible to play for 1970 season.
[citation needed] While at Rice, Barnes helped start the Black Student Union and was part of a movement to pressure the university to hire more African-American teachers and coaches.
[3] He was selected by the Dallas Cowboys in the seventh round (176th overall) of the 1973 NFL draft, after he dropped because teams were cautious of his civil rights activism.
[1] His athletic ability and production propelled him to become the second African-American linebacker to make the team in franchise history (Ralph Coleman was the first).
His best moments came in the 1973 preseason; against the Miami Dolphins, he helped stop Larry Csonka three times in a row, during a 2-yard goal-line stand and against the Kansas City Chiefs, he had 11 tackles (3 for loss) and hit backup quarterback Dean Carlson to the sidelines under the bench, which the referees thought Carlson was out of the playing field and flagged Barnes with a 15-yard personal foul penalty.
His relationship with the Cowboys also started to deteriorate,[5] with his growing belief that racial reasons were the main cause of him remaining in a reserve role.
[1] In October, he left training camp in a disagreement over playing time and salary, while also informing the team that at the recommendation of his personal doctor he was going to have knee surgery for an injury suffered in the last game of 1973.