The Lions will save at least $6.75 million off the cap with his release. Harrison had no guaranteed money but had $3.5 million of his $8.5 million base salary guaranteed for injury only. The Lions will take a $5 million dead cap hit releasing him.
But his absence could leave Detroit without its three top defensive tackles from 2019; A'Shawn Robinson and Mike Daniels are headed to free agency.
The Lions have hybrid tackle/end Da'Shawn Hand, who missed the majority of last season, and 2019 undrafted free agent Kevin Strong as the top tackles on the roster at this point.
Detroit traded for Harrison on Oct. 25, 2018, sending the New York Giants a fifth-round pick for one of the better run-stoppers in the NFL. It was his first time not with a New York team in his career.
After sitting out spring workouts last year to take care of his family, the Lions gave Harrison a one-year contract extension in August, adding a year onto his deal and converting much of his base salary into a $7.5 million signing bonus.
By the end of the 2019 season, Harrison said he was contemplating retirement after he played through a multitude of injuries and "wasn't able to ever get back to the form I'm used to." Harrison, who turned 31 in November, said if he felt he couldn't return to being the player he had been in prior seasons, he would walk away.
Originally undrafted out of William Penn, Harrison appeared in 117 games with the New York Jets, Giants and Lions, starting 110 of them. He had 485 tackles in his career with 24 quarterback hits, 11 sacks, 10 passes defended and four forced fumbles.