I suppose this could happen, yet somehow I doubt it unless the OT comes at a good price. In a way to me this has a feel of some desperation to it when there has been some noticeable improvement from the OL. I still think the team holds Fant in high regard and won't be ready to sell the farm to acquire a rental at LT. I could be very wrong but somehow messing around with a winning team at game 7 seems a bit risky.
That said, I have genuine doubts the team will keep Graham next year as he will want more than they will pay for his services. If that happens the team will acquire a fairly early compensatory pick for Graham in the following season's draft, and that is more certain than possibly re-upping an aging expensive OT. I guess the plan for the future will be revealed to some extent by what happens this trade deadline.
The team has 38 deals that end this year and there will be lots of changes. There quite a few on the roster that may need to raise their games besides Graham to be kept here after this season like: Lacy, Joeckel, Lane, Aboushi, and some of the depth on the D who won't be that expensive. I also wonder about Shead who would be worth keeping. I suspect trying to keep Sheldon Richardson will be a genuine priority however, that isn't certain b/c he might be in real demand and attract a gigantic deal from some team. That could also attract a very high comp. pick. The RFA deals are also going to be interesting.
It will be an interesting offseason, the nucleus of a strong team will still be here