Manuel Sistrunk (born June 16, 1947 in Montgomery, Alabama) is a former American football defensive lineman who played ten seasons in the National Football League. He played college football for Arkansas AM&N (now known as the University of Arkansas at Pine Bluff) and was drafted in the fifth round of the 1970 NFL Draft.
Manuel Sistrunk retired in 1976.
Manuel Sistrunk played 10 seasons in the NFL and was drafted in 1970. So he definitely did not retire after only 6 years in 1976. The system might not know exactly when he retired so it thinks it could be neither correct or incorrect.