It's a tough call and would be kind of risky no doubt. Do you move an already established LT to LG and hope you find another solid LT in the early rounds of the draft? If it works, great, then the Bills look like geniuses, but if it doesn't work, then they would look like a bunch of bumbling idiots.
The left side of the O-line used to be a strength, now it's a weakness, especially in the run game. One thing is for sure, it needs to be upgraded.