If Luke Shaw hits a bot of form (which is looking likely) then we have no need for Rose, or Sandro or Ghoulam, or Gaya or any LB.
I think Rose will come good after his injury, just building match fitness. He is undoubtedly a good player. While we have no RW and no depth in CM we have other issue's.
I just don't think we should sign for a position we do not need to strengthen, when there are more pressing issue's in our squad. Moving into next season, we'll need a RB to replace Valencia more than a LB