Maybe. But I think they can sign him to a long term deal

While I'm not sure I'd FT him, I don't think they'll have to. All they need to do is to properly judge the market and be ready to pay. And they'll make that clear to Dotson's agent. Of course, there is such a thing as a contract that is off the charts crazy and they won't do that. But they need to act very quickly, because while there's a couple of other good OGs in FA, if the Rams dither they'll lose out all the way around. They won't.