Stafford was entering the final year of his $53m (£40.9m) deal and Detroit had been confident of agreeing terms. His new deal which starts in 2018 is for 5 years and will pay him $27-million a season.
Stafford, the No. 1 pick in the 2009 draft, has started eight seasons.
Stafford is the fourth quarterback in National Football League history to throw for over 5,000 yards in a single season, being one of three players to do it in 2011 and is the fastest player in National Football League history to reach 30,000 passing yards.
In the end, Stafford's getting his rightful due-and if he keeps playing at the level he reached in 2016, Detroit will be getting a relative bargain.
On Monday, the Lions and Stafford made that long-term possibility a reality.
The Lions will counter with the argument of quality quarterbacks are hard to find and with the market value of top-tier quarterbacks escalating rapidly, they probably consider the deal with Stafford a bargain.
It is possible when Stafford's contract is up that he will have thrown for over 50,000 career passing yards and over 240-255 career passing touchdowns.
"I mean I know you can't win by yourself, but when you're making that kind of money, figure it out because Matthew Stafford has not ever won a playoff game", Smith continued.
However, Stafford's deal will surpass the deal Carr signed this summer.
Last year, Stafford threw for 24 touchdowns, 10 interceptions and 4,327 yards in 16 games.