i'd like to see them before camp, tbh, and go into camp with the team and pretty much the depth chart set or at least the starters decided upon.
TC needs to be just about making the offense/defense/STs fluid rather than trying to figure out who is going to be starting. competition needs to exist for sure, but only for depth. the rest of the team needs to be set and working on making their jobs second nature.
not realistic, but ideal.
I say that just because that is when (or more like at the end of camp) there will be the chance of veterans becoming available.