The Arsenal game makes things tricky, though. Feels like they’re stuck between a rock and a hard place—risk the league or risk Europe. Either way, this next week is going to be huge for them.
Manchester United is at a very tight spot but I'd expect Amorim to know which to give priority. If he can get a defeat against Arsenal and a victory against Real Sociedad, looks to me like a good result. They need the Europa trophy badly because it's their golden ticket to the champions league. So I don't expect him to give much importance to the Arsenal game and to hand Chido Obi and Harry Amass their first premier league start in other to rest other players for the Real Sociedad 2nd leg game.
I think Manchester United don't need much to plan for Premier League now, they should plan more for Europa League matches. Manchester United drew in the first leg match so the second leg match is really important for them. If Manchester United cannot enter the field with full strength in the second leg match, they will be far behind Real Sociedad. This season Manchester United is performing somewhat well in the Europa League so we expect Manchester United to have a good chance of winning the Europa League title at least this season. Now if Manchester United plan equally on both the Premier League and the Europa League and take both more seriously then a good performance in either one will surely have a negative impact.