Honestly when Zain and Nico redshirted in 2015, they didn't wrestle a single open tournament. Both for different reasons, Zain I imagine was eating and bulking (which is impossible if you're wrestling a season) Nico I imagine was very broken from his first 3 years and just totally needed to heal.
For Van Ness, I imagine it's a combination of both. He probably needed to put on some size to be a full sized 149 but he also has had a ton of injuries (broken leg senior year and then bulky knee brace at Clarion) Cael saw the value in having Shayne just not wrestle the season. There will be rust when he starts obviously but it doesn't matter. It's about getting seasoned and ready for March (and as healthy as possible) For the record, I thought Shayne looked ready to go after his 2nd match at Clarion (got a quick pin and was hopping up and down at center)
It goes without saying but at 149, Shayne's best competition is in the room (Zain, Nick Lee) but in an environment where Cael can make sure he's not getting hurt.