Signing Rashford is the best thing Flick has done to Barcelona this season they missed signing Nico Williams so getting Rashford even though its on loan is an opportunity to strengthen that wing since I heard he wants to use Raphinha as an attacking Midfielder. Rashford would add lots of strength to their depth and he's already fine in the training ground.
Well the coach knows what his doing and must have a reason as to why he signed Rashford even though Rashford was not the initial player they wanted to sign for that wing. But it's all good, if Rashford plays well and adapts to the team then Barcelona will definitely trigger his buy option at the end of the season as agreed with Manchester United. If Flick wants to use Raphinha as an attacking midfielder that means his going to displace, Dani Olmo and Fermin Lopez in that position because those two players are Barcelona current attacking midfielders.