ALLEN PARK, Mich. (AP) -- Detroit Lions quarterback Jon Kitna missed a third straight practice and is listed as doubtful for Sunday's game at Minnesota.
Back spasms forced Kitna out of last weekend's game against Chicago in the third quarter. He underwent an MRI Wednesday, but coach Rod Marinelli says Friday that he doesn't know the results.
Dan Orlovsky replaced Kitna during the loss to Chicago, just the fifth game in which he's appeared in three-plus NFL seasons. Orlovsky and second-year QB Drew Stanton split snaps again Friday, although Orlovsky's practice time was limited by a sore ankle.
Kitna has started 36 consecutive games for Detroit.
Marinelli says the Lions' response to a potential change at quarterback has been "fine."