To me, the pre-rut is from the time the velvet comes off, until they get heavy into the seek/chase phase. “Rut type” sign will be sporadic. You may see 2 bucks sparring pretty good & rubbing up trees, and in the same field a buck standing next to some does & feeding like they weren’t even there. As it gets later & later in the pre-rut, more and more bucks are showing “rut-type” behaviors. Eventually you hit the seek/chase phase where a few does are in, and nearly all the bucks are looking.