Horton (groin/shin) was a non-participant at Thursday's practice, John Boyle of the Seahawks' official site reports.
Horton was listed as full following Wednesday's walkthrough with a groin injury, but a shin issue was tacked on Thursday that didn't allow him to mix into drills. It's a concerning development just three days before Sunday's game versus the Cardinals, but his status nonetheless will be watched closely to see if he may be in danger of sitting out Week 10. Jake Bobo (calf) and Dareke Young (quadricep) also haven't practiced this week, while Cooper Kupp (hamstring/heel) upgraded to limited Thursday, so a number of question marks remain in the Seahawks' receiving corps.