Franchise tag
As with the other pending free agents that have been covered, the easiest route to get Villanueva under contract next year is by giving him the franchise tag. The Steelers will be cap-strapped next year, so getting into a free agent bidding war for Villanueva will likely end with him on a new team. As well, unless the team gives him a top contract from the get-go, it wouldn’t make sense for Villanueva to sign, as he could be losing out on millions by settling for a contract from the Steelers.
The NFL luckily categorizes the franchise tag under offensive lineman, which lowers the overall hit of it. That said, it is still projected to be $14.87 million next offseason, which would nearly be impossible for the team to fit under their cap. Even if the two sides agreed to a contract extension, later on, they would still have to account for that hefty cap hit from the tag in the short term. That means making some major cuts and allowing most of the other free agents to walk in order to give him the tag.
This means that more than likely, Villanueva will end up entering free agency at the end of this season and will likely sign a good-sized contract with a new team. Unless he has such a strong desire to remain with the Steelers that he takes a huge discount (not likely to happen), Villanueva will earn a nice pay raise from a different team.