Quinn had to kind of dummy his defense down in the back half of last season in order to keep gap integrity vs the run. That's one reason why he was so eager to get Mazi.
The defense that Quinn wants to call is basically modern ameoba-front positionless football. He'll throw weird fronts at offenses and line up in weird gaps, then stunt on top of that. His basic defensive concepts are pretty simple - he's a single-high man type guy - but he throws a ton of disguises at offenses for both coverage and pass pro.
Parsons may be a DE, but it's not like he's gonna just line up at 7 tech and get sent at the LT's outside shoulder all day. He will still be lined up all over the front.