Antonio Gates, Tight End, Los Angeles Chargers
An undrafted free agent in 2003, tight end Antonio Gates was a trailblazer in the NFL, in terms of being the first college basketball player to successfully convert to tight end in the NFL. He is the Los Angeles (and formerly San Diego) Chargers franchise record-holder in receptions, receiving yards, and receiving touchdowns. In 2015, he became the second tight end and ninth player overall to record 100 career touchdown receptions. But since the 2015 season, Gates has began to show a visible decline in his production and abilities. His yards per reception have gone down every year, and the Chargers have already began to utilize his replacement — tight end Hunter Henry — more often than Gates.