I think I know what the OP is referring to...
One thing you have to understand is the ILB/MLB (wagner) much like our WSLB Jones is they have responsibilities to cover their portion of the field. It's worth noting that I have seen Wagner take on Jones responsibility more than once. When I see Wagner run past Jones on the opposite side of the field that shows me two things. One Wagner being a savvy vet and is quick to read plays. Two, Jones is not doing his job some of the time. He gets washed out or is slow to diagnose a play. Another note is Wagner has never been a good cover LB. If he's ever covering a slot receiver or a George Kittle, then the Rams defense has essentially already lost the play. Sometimes offenses out scheme our defense. It happens.
As others have said he's been rated the No 1 MLB up until this point of the season. I doubt yesterdays game helps his cause but the man has been playing lights out. That's more than I can say about the other plays around him. IE Rapp, Jones, and some of our inexperienced DB's. Whom we saw get outplayed and outsmarted yesterday.