Too much contrast to the way we need to play and the personnel needed to do so between Sanchez or Giroud as CF.
The former enjoys space and being on the ball in his high risk v reward style which is fine as CF, but counter productive as WF as he drops deeper to cover the FB and plays from behind the line and can turn over possession trying too much on the ball. Likewise Giroud no longer looks to create/vacate space in the middle which also closes the running lanes ahead of Sanchez.
Giroud also works better with the likes of Ramsey, Walcott & Wilshere running off him in close support and playing as pivote in zone 14.
Issue of late has been AW trying to fit in both camps like he did at the start of the season.
So far as injuries go AW could have used Lucas as CF or cover for Walcott, and still looked to use Giroud from the bench in what has been our most successful period of the season.