Detroit placed the non-exclusive franchise tag on the defensive end Monday, the last day the team could prevent him from becoming an unrestricted player on the free agent market next week.
The non-exclusive tag allows other teams to negotiate with Avril, but gives the Lions the option of matching the offer or letting him go in exchange for a pair of first-round picks from the team that signs him.
If Avril doesn't sign a long-term deal with Detroit or another team before July 15, he will have a one-year contract with the Lions for $10.6 million - the average of the five highest-paid players at his position.
Detroit general manager Martin Mayhew has said he didn't plan to use the franchise tag and Avril made it clear he didn't want it.
The 25-year-old Avril has 19 1/2 sacks the past two seasons and 30 in his four-year career. He was a third-round pick out of Purdue in the 2008 NFL draft.