This is exactly what happened to Alex at arsenal. Looks like he is finally developing into the player he could be, bad injury, out for x amount of months, takes a while to find his feet again, begins to play well, then big injury again. The only bad habit he picked up at arsenal was picking up injuries.
In all fairness, maybe Liverpool are managing his knees better and are ensuring a repeat does not happen again. Something maybe Arsenal should have done with a whole lot of their players...
Klopps statement clearly says that for what we are trying to achieve here and the long term interests of the player. So yeah, why rush the player. He is young and will have ample amount of time to establish himself.