New Orleans Saints tight end Jimmy Graham lost his case to be paid like a wide receiver with his franchise tag and will be forced to play for just $7m (£4m) in the 2014 season, despite being one of the most productive players in the NFL.
"I can think of a few terms to describe what's going on in the NFL, like 'backward,' 'lack of common sense' or 'behind the times,'" Gonzalez wrote on CBSSports.com.
"But the one that makes the most sense is 'discrimination'. Salaries should be set based on production and contributions, not positions."
Gonzalez retired from the game at the end of the 2013 season after a 17-year career.