Mike O'Hara, who works for the Lions' official site, first reported the news (h/t MLive.com's Kyle Meinke), saying Stafford had "broken bones in his back."
The injury provides some context to what was one of Stafford's worst seasons in the NFL. He threw for 3,777 yards, 21 touchdowns and 11 interceptions. Football Outsiders ranked him 20th in DYAR (defense-adjusted yards above replacement) among the 34 quarterbacks with at least 200 attempts.
Stafford acknowledged last December he was dealing with a back injury.
Meinke also wrote the 31-year-old was noticeably at less than 100 percent when he spoke to reporters ahead of Detroit's 31-0 win over the Green Bay Packers to wrap up the regular season: "You should have seen him when he dropped the cap to his water bottle after his press conference on Sunday. My grandfather bends over better than that. Stafford, who has battled back pain for more than three weeks now, is hurting."
Meinke noted Stafford wanted to keep his consecutive games streak going, which now sits at 128. Based on the severity of the injury, though, it seems fair to wonder whether he should've stayed on the field.
Stafford was injured in Detroit's Week 13 loss to the Los Angeles Rams, which dropped the team's record to 4-8. By that point, the Lions' playoff hopes were basically gone, so the 2014 Pro Bowler wasn't going to change the trajectory of the campaign.
In May, ESPN.com ranked the Lions 24th and gave them a 17.4 percent chance of reaching the postseason in 2019. Since he will have had a full offseason to let his back heal, perhaps Stafford can get back to his best next year, which is Detroit's only hope to secure at least a wild-card berth.