Barcelone were shocked 1-2 at home by Alaves last weekend and only a thumping win would confirm that the defeat was merely an isolated case, reports Xinhua.
Barcelona reacted to their weekend defeat with a 7-0 thrashing of Celtic in the Champions League on Tuesday. Coach Luis Enrique rested key players against Alaves and paid the price.
It remains to be seen the combination of players Enrique chooses on Saturday keeping in mind the vital home match against Atletico Madrid on Wednesday.
Enrique is likely to make some squad rotations and it is almost certain that he will start with the attacking trio of Leo Messi, Luis Suarez and Neymar that shredded Celtic to pieces.
Other regulars such as Ivan Rakitic or Andres Iniesta may be given a rest, while Javier Mascherano could also return in central defence.
The form of Andre Gomes against Celtic showed the Portuguese midfielder will add muscle and guile to the side, while new signing Samuel Umtiti must also be happy with his display.
Leganes are enjoying life in their first season at the top-flight, despite a 1-2 defeat away to Sporting Gijon a week ago when they paid for errors in the first half.
The side coached by Asier Garitano has already held Atletico Madrid to a draw and is likely to play a five-man defence. Barcelona will have to move the ball a lot faster than they did against Alaves' five-man defence if they are to break down their rivals.
Patience is likely to be a necessary virtue, but with memories of Alaves still fresh, an early goal would go a long way to calming Barcelona's nerves.