There's no reason for him to be on the defensive sideline. The difference right now is, Kai is a bigger, more physical guy. Zach is just growing into his physical stature. Hundley likes to play two-deep at linebacker, rotating players in and out based on down and distance. Both Ellis and Tuiasosopo have what coaches frequently call great motors, meaning they don't halt their frenzy until the whistle blows.
Great motors cause players to chase quarterbacks during non-contact drills.
Great motors tend to get guys on the field. Tuiasosopo said he has no problem, however the competition plays out. But I have four more years left. I'll do whatever the coaches ask me to do. The soft-spoken Ellis takes the same tactful approach, which shouldn't be surprising.