I've always assumed that Brockers was not going to make this year's roster. Trading him even for a 7th rounder makes a whole lot of sense. Losing Fox is a bigger loss than Brockers. But even then Fox has only one year of real production during his time with the Rams. With Jonah Williams and Hoecht the Rams have options. IMO Williams might end up an upgrade to Brockers.
If Lewis can stay healthy they will be set on the starting D-line with Floyd, AD, Robinson and Lewis/Williams. These are IMO expected roster loses, and not necessarily significant losses. Floyd and Darious Williams have always been the key players to extend and both would seem to be locked up. They have restructured Whitworth so the only question will be Havenstein. IMO Rob will be a post June 1 release if not traded. They can then play Noteboom at RT for 2 years before moving him to LT when Whitworth finally retires.
So far I see nothing that raises any concern.