I think the coaching staff sees Avery (next year) being close enough to Will Howard's ability that they'll be ready to move on. Additionally, developing Avery now will put us in the best position for the CFP beyond next season.
Meanwhile, Will's season is putting him in football purgatory where he's pretty good but also not a likely draft pick. The NFL will love his smarts and size though so who knows. If Will wasn't happy here, though, he would've left long before now. Dude's stuck it out through a lot.