I'm going out on a limb and saying, IF detroit drafts an offensive lineman, whether it be Robinson, Mathews or Lewan -- they will be immediate starters on the OL.
Mathews or Lewan would probably take over at LT and Reiff moved to RT, as Reiff is very good at run blocking. Robinson is the best run blocker in the draft and while Waddle was solid last year -- Robinson would be a big upgrade at RT and help the run game immediately.
So if Detroit drafted an OL -- it wouldn't be done to have them as a backup -- it isn't like the year we draft Reiff and we had multi-year starters in place -- Our RT and LT were both 1st year starters. I was reading somewhere, I'll have to see if I can find it -- the OL, who went 1,2 and 4 last year would all be picked lower than the top 3 OL in this year's draft. Obviously that is just someone's opinion, but if Detroit can add a road grader to the OL, it would only make the offense that much better, as team's would have to respect the run and couldn't leave their safeties 20 yards off the line of scrimmage.
I'd actually be happier to see the Lions take someone like Mathews or if by the grace of god, Robinson dropped to 10, than a WR. Robinson would be the perfect fit for the Lions. Put him next to Warford and the Lions could have one of the better run blocking lines in the NFL, when you add in that Reiff's strength is also run blocking.
From everything I read on this board, the consensus seemed to be that the O-line is great. Considering how young they are and the fact they only played one year together, they'll only get better as a unit. If this board believes that, why would you draft a replacement for any part of it other than Center? I don't believe that they were great. I thought they played pretty well considering. I feel like Stafford was having to get rid of the ball to fast at times. I think that will improve. Why draft a position that may not even be an upgrade? WR3 is a hole. We don't have a hole on the O-line. Doesn't make any sense to me.
For the record, I don't want a WR with that pick. It would make more sense than an O-lineman though.