Strachan (concussion) has been ruled out for Saturday's game with the Vikings, James Boyd of The Athletic reports.
Strachan didn't show up on the team's injury report until Wednesday, so it appears he may have suffered the concussion during practice Tuesday. With the Colts on a short week and the late addition to the injury report, Strachan would have been hard-pressed to clear protocols ahead of Saturday's contest. His next opportunity to suit up will be Week 16 against the Chargers.