The Reds travelled back from Spain after a 1-1 draw with Real Sociedad sets things up for an intriguing Europa League round-of-16 second leg at Old Trafford on Thursday.
Amorim spoke to journalists at the Reale Arena before boarding the plane and was asked about team news for the 16:30 GMT kick-off against the Gunners.
While admitting Chido Obi is an option to play against his former club, having not been eligible on Thursday, Ruben was clear that he will have to properly assess his squad in the build-up to the game against Mikel Arteta's men, who hit PSV Eindhoven for seven in the Champions League on Tuesday.