It will certainly be harder once they get into the secondary. I'm just thinking of all the helmet to helmet hits RBs take close to the line that never get called. I guess it's technically because they are not defenseless but it seems just as dangerous or more so than QB hits and WRs over the middle. Those guys take a beating near the line and nothing ever seems to get called.
Anyway, I just hope our line/scheme is good enough this year that we can see Kamara running free in the secondary instead of getting hit 2 yards behind the LoS. I'm also hoping for a healthy Kendre Miller. That dude runs with serious violence when healthy. He's going to be a load to bring down.