The franchise tag for offensive linemen is $14.78 million.
"Joe has been a model teammate and an essential element to our success since joining our team in 2016," the Patriots said in a statement. "Utilizing the franchise designation allows both sides more time to try to reach the goal of a long-term agreement."
Thuney, 27, was expected to generate significant free-agent interest because of his combination of age, durability and top-of-the-line play at left guard.
That's the ideal trifecta and why Thuney, who started every possible game over the past four seasons (74, including playoffs), was one of the best players on the free-agent market.
In 2019, Thuney had a 97% pass-block win rate, according to ESPN's metric that uses NFL Next Gen Stats to determine which linemen can sustain their blocks for 2.5 seconds or longer. That was second best among all guards, behind perennial All-Pro Marshal Yanda of the Baltimore Ravens (98%).
The Patriots selected Thuney in the third round of the 2016 draft out of NC State, moving him from tackle to guard. The selection (78th overall) was ultimately part of the compensation the team received for trading Pro Bowl defensive end Chandler Jones to the Arizona Cardinals.
Thuney became the first player in NFL history to start in the Super Bowl for the first three years of his career, according to the Elias Sports Bureau.