I just recently watched the injury vid (earlier today) and double checked even that due to your comment and if you mean injured by jacked up then I absolutely agree. However, even on that hit he knocked the ever loving manure (Fulmerized for the benefit of VN rules

) out of his opponent and did so all game prior to that injury. In fact, he did so his entire career here.
However, Inky's injury was also a freak injury on a play that very much looks like he should've bounced right back up. If you watch it again (I even slowed it down) it doesn't make sense and the extent of the damage makes no sense whatsoever as even a brutal hit doesn't typically cause that but sometimes freak injuries just happen. You hit at exactly the right spot and it's devastating whereas most of the time harder impacts. Force based impacts that are in the usual spots tend to do very different sorts of damage than Inky's injury. And of course, your own mass adds to the potential damage for more common impact injuries, especially when moving at a higher rate of speed.
Tiny RBs and others are living proof that you don't have to be particularly big to play against very large players and take the hits that go along with it - one of the reasons the little guys tend to bounce right off unless the hit is delivered properly is because they're small.
At any rate, all I'm saying is Rashaan may be ok at a lesser weight until he can add more with time and that I don't think it's something that automatically = red shirt.