Irvin (6-foot-2, 295 pounds) was a third-round draft pick by Carolina in 2009. He appeared in six games last season for Dallas, finishing with three tackles and no sacks.
It would have cost around $7 million on a one-year deal to use the tag on tight end Brandon Pettigrew and keep him entering free agency.
This is the second straight year the Lions haven’t used the tag. The last time they did was for defensive end Cliff Avril in 2012.
The tag allows a team to keep one player each year from becoming a free agent but it often comes at an extreme price — typically the average of the top five salaries for players at that position — for the one-year deal.
General manager Martin Mayhew has said that re-signing Pettigrew is a top priority, but the tag price made no sense in this case because it would have put the club too close to the salary-cap limit again.