Thornton (shoulder) isn't practicing Wednesday and may soon be placed on injured reserve, Mike Reiss of ESPN.com reports.
Thornton is in danger of missing the start of the season but should be healthy at some point this fall. It isn't clear Thornton would be handling a key role even if healthy, as he appeared to slide down the receiver depth chart this summer even before missing practice. The Patriots have three veterans starters in JuJu Smith-Schuster, DeVante Parker and Kendrick Bourne, plus two sixth-round rookies in Demario Douglas (shoulder) and Kayshon Boutte.