The Lions can’t sign DE Cliff Avril to a contract extension until next offseason after the two sides couldn’t come to agreement on a multiyear deal before the July 16 deadline for franchise-tagged players. A decision on the long-term future for Avril, who’s guaranteed a salary of $10.605 million once he signs the tag, isn’t the only one looming among the DE corps. Reserve DE Lawrence Jackson is slated to be an unrestricted free agent in 2013, and fellow backup DE Willie Young could become a restricted free agent next offseason. Also, DE Kyle Vanden Bosch enters the final year of his deal in ’13, when he’s slated to make $5 million in salary. Avril, 26, notched 11 sacks in 2011. Were the Lions to give him the franchise tag in 2013, he would receive no less than a 20 percent raise over his ’12 salary. A multiyear contract would lower Avril’s salary-cap number and secure a key part of the defense who’s in his prime.