This 2015 season Snead/Fisher sure went after OL'ers who had a ton of starting experience. In addition these rookies have serious OT experience attached. Havenstein pure ORT, Brown primarily OLT/ORT, Donnal ORT/OLT, Wichmann mostly OG with some ORT, Battles OT, Williams OT. Have I made my point here.
Boudreau's current plan appears to move Brown from OLT to ORG. Boudreau has a history of doing this. Harvey Dahl was a OT till he met Boudreau. Garrett Reynolds was a OT till Boudreau move him to OG in ATL. Justin Blalock was primarily a OT in colleg till Boudreau moved him to OLG where he had many all pro seasons. Saffold was a OLT/ORT till Boudreau move him to a OG. Brandon Washington was a OLT until Boudreau move him to OLG/ORG. Mike Person was a ORT until Boudreau moved him to OLG.
I think Boudreau desires Ol'ers like listed above over those just pure OG prospects.