Who plays LT if Whit is hurt or underperforms?

Trying to look at this offseason from a birds eye view, the issue that I see as most likely to derail us next year is OL. We had great OL play AND great OL depth this year. The one loss that I see no contingency plan for is Whit at LT. Do we have anyone really who could step in there and play at a competent level? I see that as a high priority for this offseason.