so obvious what the intent is.

The first play you referenced shows a much smaller DB diving at the legs of big RB and it looks like he takes a knee/leg to the head (hint of a limp arm for a bit as he slides after the hit). A lot of bell-rung plays cause players to jog off the field as if nothing is wrong, as they don't want their own team coaches/docs taking them out of the game.

The second play? Looks like he is rushing off the field to get a sub in, and it's pretty clear he took a pretty good hit to his knee, even if he was able to come back and play after half.

So who knows. Certainly we see players faking injury to catch breath, etc. But with player health paramount, I'm not sure what you do.