At D3 , you would want to make sure that OL, that you want to get as much playing time as possible, is in the first 5 players in the OL depth chart collum, D2 and higher you have more options with the user 1 and 2 spots... Check the formations tab to see which spot correlates to depth charts, again more relevant in D2 and up. Just a thought ... If that OL is not as good as say 5 other OL set him at 6th on the depth chart and a lower sub % and the other "better" 5 at say 90% or 95 depending on their stamina.