Yeah, it makes no sense to release someone to keep a kicker you're not even using on the roster. From what I'm seeing, McManus is still dealing with that injury, and if that's the case, pit him on IR and let Haversik fill in while he completely heals. And if the team knew this when activating McManus for the game, that missed field goal looms even larger and is roster malpractice on the part of whoever is responsible for whoever fills out the game inactive list.