For potential 2018 starters, the Rams need to look to FA for 2 positions: NT and in-line TE.
Especially the Vikings game highlighted the need for both (although I've posted about this since early in the season).
If the D wants to come out swinging next year and not continue to give up big numbers rushing, they can't wait for a rookie NT to develop. You can get one for a pretty decent price FA. Typically, these are 6 + year vet DTs with nicknames like "pork chop" who aren't mobile enough to play 3-4 DE or a penetrating 4-3 DT. But, they have plenty of experience, know how to use their hands, and can stuff up a middle within about a 3 yard radius.
Same with in-line TE. Don't need a great route-running athletic TE. We need a big, tall, physical blocker who can reach up and catch a ball if thrown to him within about 5 -10 yards of the LOS and in the Red Zone. A Kyle Rudolph type. A guy who can battle DEs and not get run over. A guy who can set an edge.
