If you have an offense which is chronically slow to start the season, see Washington for the last 6 years, there is some benefit to getting them into a rhythm before week 1. Whether that out ways the injury risk is the question. They are just as likely to get injured in Q1 of week 1 as during the Pre-season if they are lacking in real game speed fitness. I will trust in the coaching staff and reserve the right to irrationally criticize them later on if the team don't go 5-0 to start the season
