Coates didn't play football until his senior year at Greenwood High School, and was a multi-sport player at Livingstone College located in Salisbury, North Carolina.
As a gridiron player at Livingstone, he broke nearly all meaningful records at the school, but due to his split-sport performances against small-school opponents, he received little notice outside the CIAA.
His career changed with the 1993 arrival of quarterback Drew Bledsoe and head coach Bill Parcells to the Patriots franchise.
In 1994, his breakout year, he caught 96 passes, the most ever for a tight end to that point,[4] breaking a record previously set by Todd Christensen in 1986 (the record was later broken by Tony Gonzalez in 2004), for 1,174 yards receiving, the only time in his career he would gain 1,000 yards in a receiving season, while also scoring seven touchdowns.
He subsequently played for the Baltimore Ravens, where he climbed the all-time receiving charts and won Super Bowl XXXV in the process.
When Coates was released by the Ravens in the following year, he decided to retire, having become the fourth all-time leading receiver at tight end in NFL history, behind Ozzie Newsome, former teammate Shannon Sharpe, and Kellen Winslow.