I would expect that we should have some idea by the end of training camp and preseason if Walker can handle the LT spot. He certainly did not generate any alarms when he played there last year, but I imagine the coaching staff would thoroughly test him with outside speed rushes to see if he can deal with them.
My concern, as people have noted, is what happens if he stinks up the joint? People who think Bell can step right in this year are deluding themselves. I would have thought Chambers would be given the task, but that doesn't seem to be the plan, nor does it make me all warm and fuzzy inside.