We'll see how Rashford performs at Barcelona, whether he can improve his form or whether he ends up just sitting on the bench. Barcelona has a number of quality players, and if Rashford doesn't work hard to reach his best, it's not impossible that he'll end up on the bench. Barcelona brought in Rashford on loan solely to add depth to the squad, and if his presence doesn't make an impact, Rashford won't be an important part of Barcelona so this needs to be considered by Rashford as a step to restore its curry..
Rashford can't afford to be lazy if he wants to become a key player in the Barcelona squad, and he must also be able to work with the existing players in the squad. If he continues to show his ego during any match, he may not get more minutes in the Barcelona team and won't be signed permanently by Barcelona after his loan period ends. I also want to see how Rashford adapts to the other players at Barcelona, as they were generally good players, judging by their performances last season.
I don't think he'll show any sign of laziness cause if you want to be a serious player and get playing time at Barcelona then you'll have to be very hardworking on and off the pitch especially on the pitch, even Lewandowski that's older workers hard then why wouldn't Rashford, Hansi Flick is a no nonsense coach be won't tolerate any form of laziness from Rashford, I believe that on his first training he'll see for himself and see reasons to give his best so they'll be permanently buy him into the team, failure to do so would get him sent back to Manchester United and Rashford won't want that.