Quin originally signed a five-year $23.5 million deal in Detroit after playing out his rookie contract in Houston. In 2017, the Lions handed the 2014 Pro Bowler a two-year contract extension worth $13 million, with $9.5 million guaranteed.
Detroit will save $6.25 million on the salary cap by dumping Quin while taking just a $1.67 million dead money hit.
"We thank Glover for his countless contributions to the Detroit Lions during his six seasons with our team," Lions GM Bob Quinn said in a statement. "Since joining the organization in 2013, Glover exemplified everything it means to be a true professional in this league -- as both a competitor on the field and a leading voice in the community. Coach (Matt) Patricia and I have the utmost respect for him as a man and player, and we wish him nothing but the very best in the future."
Moving on from Quin comes as no surprise. The 33-year-old started all 96 regular season games in his six-year career in Detroit, but his play noticeably fell off in 2018. For context, Pro Football Focus rated Quin's play a 66.1 (58th among all safeties) in 2018 a year after he graded out at 90.6 and could have been considered an All-Pro snub.
After Quin noticeably lost a step this season, the Lions should skew young at safety. Tracy Walker played well as a reserve in his rookie season and figures to get a chance to win the starting gig with Quin gone. The Lions also have former Patriots veteran Tavon Wilson and converted corner Quandre Diggs, who played solidly last season, at the safety position.