Not sure if that's what you meant by using his junior year to do so but was a redshirt soph. That's a bit different than someone who was already a junior or senior. And the others are examples of special circumstances. Also players who were expected to contribute/be starters. I just say "no chance" for guys where it's pretty clear as day there's just no reason. No injury, non contributor, just let them run their course. I also don't agree with a statement someone made that it is "cut-throat" to not use one when it is available. Like you said, sometimes they just push them through.
I got you though. Technically they "can." Just extremely unlikely and virtually never happens in some circumstances. Speaking of redshirts, it would be pretty crazy to have Lapuaho next year. Obviously be very nice to have him this year, but if an extra starter-caliber guy helps in 2018, that will be killer. Especially to help with losing 3 major seniors.