Stafford's name made a surprise appearance on the Lions' injury report Friday as questionable because of a hip injury. A source told ESPN's Dan Graziano that Stafford's issue is actually with his back; he has had problems with it in the past and it flared up again this week.
Stafford, 31, had not been listed on the injury report before Friday and has not been sacked since Week 1 against Arizona. He was spotted in the locker room following practice Friday and did not appear to be limited in any movement.
He has started 131 consecutive games for Detroit, dating to the start of the 2011 season. He has played through injuries before, including a back ailment in 2018 and torn ligaments in the middle finger on his right hand in 2016. His string of starts is the third-longest active streak among quarterbacks, behind Philip Rivers and Matt Ryan.
Stafford's pain got worse as the week went on, and one source said, "This is the closest he's probably been to not playing, but he's planning on going."
Two weeks ago, when Detroit's opponent was Rivers and the Chargers, Stafford explained being able to start as many games in row as he and Rivers have.
"I think there's a lot that goes into it," Stafford said. "Some of it is luckily being able to play through some of the stuff that you have. Sometimes you have stuff that the quarterback position can't play through. Other times you can.
"It's not like he's had however many starts and he feels awesome every time he goes out there. But he's been able to battle through that stuff and play."
Stafford has completed 67 of 107 passes for 831 yards, six touchdowns and two interceptions this season.
The Lions are also without Pro Bowl cornerback Darius Slay (hamstring) and starting slot receiver Danny Amendola (chest). Slay was very limited in practice all week and Amendola didn't practice Wednesday or Thursday, but returned on a limited basis Friday.
With Slay out, Mike Ford is expected to get the start against a dynamic Kansas City offense -- a massive ask for the second-year pro from Southeast Missouri. Amendola's absence can be filled in a variety of ways, including using two tight end sets with T.J. Hockenson and Jesse James or receivers Marvin Hall and Tom Kennedy, who was promoted from the practice squad earlier this week.
ESPN's Jeremy Fowler, Adam Schefter and Michael Rothstein contributed to this report.