Bruss will be back. Let's hope that pans out.
Allen is the guy they like. Not just for pass and run blocking but for his chemistry with Stafford. Here to stay (I'd draft his replacement though).
Havenstein is on his last legs but he's the one stable cog.
LT will either be Jackson or Noteboom. Rams made thier bed on that one.
Two guys in the draft I love:
John Michael Schmitz- I think you can play him at left guard and then move him to center once Allen's contract is up. 320 pound athletic menace on the interior.
Jaelyn Duncan - dancing bear. Smooth pass sets. Could possibly play him at LG as a rookie too.