Ernesto Valverde's side are still unbeaten in the Primera Division and are nine points clear of second-placed Atletico (in action in the Madrid derby this weekend against Real) with eight games left to play.
Barca, having come back from 2-0 down to draw 2-2 at Sevilla last weekend, beat Roma 4-1 in the teams' Champions League quarter-final first leg on Wednesday night and meet the Italian side again on Tuesday at the Stadio Olimpico for a place in the last four.
Leganes comes first, however, and here Goal takes a look at everything you need to know ahead of Saturday's game...
Sergi Samper and Lucas Digne are both sidelined, while Sergio Busquets is doubtful after returning to action on Wednesday night and ending with some difficulties in the game against Roma, when he was substituted midway through the second half.
Meanwhile, Lionel Messi is fit to start again – as he did on Wednesday – following his recent hamstring and adductor problems.
Valverde has no players suspended for the game against Leganes on Saturday.
Barcelona potential starting line-up
With the Champions League quarter-final second leg ahead against Roma on Tuesday, Valverde is set to rotate for the visit of Leganes.
Luis Suarez and Messi both look likely to start, although one of the two could be rested or withdrawn later on in the game.
Busquets should be kept in reserve after he returned from injury on Wednesday, along with Andres Iniesta, while Philippe Coutinho (cup-tied in the Champions League) and Ousmane Dembele are set to start.
Thomas Vermaelen could come in for Samuel Umtiti at the back.
Leganes team news
Leganes lost 1-0 at home to Valencia in their last match, having previously beaten Sevilla 2-1 at Butarque.
The capital club, who were Copa del Rey semi-finalists after knocking Real Madrid out of the competition, are in 14th place in La Liga and still need a few more points (they currently have 36) to guarantee survival.
Winger Alexander Szymanowski is sidelined, while defenders Joseba Zaldua and Martin Mantovani are doubtful. Left-back Diego Rico is suspended, so Unai Bustinza is likely to move across from centre-back to fill in there.
TV channel & kick-off time
Barcelona versus Leganes kicks off at 20:45 local time on Saturday and will be broadcast live in the UK (United Kingdom) on Sky Sports Football from 19:40 BST.
In the United States, the game can be watched live on television on beIN SPORTS and kicks off at 14:45 ET.
Best Opta match facts
Barcelona are unbeaten in their last 37 La Liga games (won 30, drawn seven), only one fewer than the all-time La Liga record set by Real Sociedad between 1979 and 1980 (won 21, drawn 17).
Only Atletico Madrid (19) have kept more clean sheets than Barcelona (18) and Leganés (12) in La Liga this season.
Lionel Messi has scored 26 goals in La Liga this season, more than the entire Leganée squad combined (25).
Luis Suarez has scored 12 goals in his 12 La Liga appearances in 2018.
Asier Garitano is winless in his three La Liga games as a coach against Ernesto Valverde (drawn two, lost one).