Robinson wasn't a surprise pick. He is a player who has the potential to be one of the best offensive tackles in the league, or a great guard if the Rams plan to develop him there.
A few questioned why the Rams would draft Robinson? He hasn't played guard since high school, and the Rams bookend tackles Jake Long and Joe Barksdale have been pretty good.
Look at it this way, the goal of a team picking in the top five is to get an elite player. Robinson was the best one on the board. The thing with Long and Barksdale is that we can wait until next season to see what happens to them. There's no reason to think about it now. Barksdale will be a free agent next season and just because he played well with the Rams doesn't mean that he would want to sign back to the team or that the Rams would bring him back. Then you have to look at Long and think can he really play LT at a high level for a couple more seasons.
My thinking is that Robinson will play left guard next to Long who is a good pass blocker. Both of these guys should blow defenders away on that side of the ball. Running back Zac Stacy and the others shouldn't have to worry too much about the push up front.
Robinson's future will probably be at left tackle, Jake Long's future replacement. It really just depends on whether or not Robinson can become as good of a pass blocker as people hope that he will be.