Fair chance?
Only two years (actually less than two years if you believe the rumors).
Substandard QB play. When opposing teams readily state after games that their strategy was to make TT try to be a QB, that is a problem.
Depth of injuries and injuries to key players (WR and safeties in particular).
Suspensions.
Key defensive player deciding to go on strike because he had to cover a handful of times during the year.
If you do not believe that having key players out (e.g., Marcell, Kyle, Aaron, Cordy, Regland, Sammy, Woods - and in many cases their backups and, in some, back ups to the back ups) affects the success of a team, one only need look at the Sabres' record with and without Jack Eichel.