I like the move.
Right guard is the proverbial tip of the spear in the run game. If the RG controls (drives?) his DT, then it sets up the rest of the OL to build on that success. If the RG falters and the rest of the OL is left to compensate (hold? clip?), the phalanx is doomed to shatter under an avalanche of swarming defenders.
Frankly, Saffold wasn't getting the job done, or at least not as much as we would have hoped based on his success at RG a few years back. Brown is more of the body-type to do well in that role than Reynolds. Reynolds is more well suited (imho) to the LG position which is more about walling than driving.