Thornton started at wide receiver Saturday's 20-12 preseason loss to the Rams, according to Sam McDowell of The Kansas City Star.
Thornton did not draw a target in Saturday's contest, but he played only six snaps and left the game before both Jalen Royals and Cyrus Allen, which is an indication the Chiefs are comfortable with where he stands. Allen has made noise during the preseason, but Thornton presumably remains the favorite to open as the third receiver behind Rashee Rice and Xavier Worthy (shoulder).