Couldn't pick a worse time to be shaky at LB. The Rams will punish this weakness to no end.
Maybe LBs with nothing on "film" would be better vs the Rams.
It was the Rams Zone Blocking Scheme which they tweaked specifically for the playoffs that started the current problems on defense for the Cowboys.
The Rams tweaked their ZBS specifically to target the Cowboys LBs.
They studied the assignments for all Cowboys front 7 players on running plays and tweaked their blocking/running scheme based on knowing how the Cowboys front 7 players react to specific run plays.
It's not the fault of the LBs per se. The predictable assignments of the Cowboys DL make it possible but the LBs were the focus.
The Rams knew that even if the DL executed their assignments that in specific situations the LBs would be vulnerable.
On the outside zone which always has a cut back option, the Rams had the RB "read" specific Cowboys defenders and stay outside or cut back based on how quickly the defender(s) moved outside (or didn't).
The Rams OL were in sync with the RB in terms of "reading" the key defenders. The RB could always make at least of 1 of 3 defenders make the wrong decision.
When 2 of 3 made the wrong decision it was a big gain. If 3 of 3 were wrong then it was probably a TD unless Jeff Heath could make a miracle open field tackle of an NFL RB at full speed and no other defenders in sight.
This season other teams just copied the Rams and the Cowboys attempts to counter it have made the problem worse and/or weakened the pass defense depending on the specific game/opponent.