Richburg played in just four games with the New York Giants last season because of a concussion, and he wasn’t happy when he was placed on injured reserve in early November with nine games remaining. The starting center thought he was on the verge of returning, and he was eventually cleared several weeks later.
The second-round pick out of Colorado State in 2014 had missed just one game in his first three professional seasons.
Richburg became expendable after former Canadian Football League star Brett Jones played well in his place.
Richburg, 26, was the Giants’ starting center each of the past three seasons. He played guard most of his rookie year.
ESPN’s Jordan Raanan contributed to this report.