The interior D-lineman have been out a mix of time during the 4 losses, but I think Reid going down was a bigger factor.
If O'Toole and Reid are 100%, the defense plays at a much higher level. Having our best edge rusher (O'toole) makes a noticeable difference in the amount of pressure we can get and helps the secondary. And the LB's suffered without Reid, we didn't have someone step up and take the D QB role effectively (Or the O QB role effectively ba dum tiss).