I think they were thrown for a loop by the Brown injury. They went thru camp & preseason with him at RT and Onwenu at LG, and I think they felt good about the way that line was performing. Then when Brown got hurt in G1, they expected him back in a week or two, so why mess around with Onwenu when there's some backup RT's that should be able to step in? If they'd gotten a proper read on that injury as a 9-10 week absence, they likely would've moved Onwenu to T. It was only when Brown went on IR, together with the overall performance of the line, that they felt moving Onwenu made sense.
I think in their minds their best line is Wynn at LT, Onwenu at LG, and Brown at RT. That was their plan all along, and they saw it working in preseason. When a line locks in, all 5 guys get better at once. They think Onwenu can be an all-pro OG, and like having a guy his size in the interior. And they may prefer Wynn's quickness on the outside, and also are assuming that Brown's return will cause everyone's play including Wynn's to step up.
