Neymar and Alba have been out since suffering injuries in the King's Cup defeat by Real Madrid on April 16, while Pique has not played since the Champions League quarter-final, first leg against Atletico on April 1.
"The three players have accelerated their recuperation from their respective injuries in the past week so that they can be available to the coaching staff for the Atletico game," Barca said on their website.
"After a few days working on the sidelines, Pique, Jordi Alba and Neymar joined the group again," they added.
Saturday's clash at the Nou Camp will be only the third "winner takes all" match on the final day of the campaign in La Liga history and the first since 1951.
Atletico, seeking their first title since 1996, are top on 89 points, with Barca, chasing their fifth crown in six years, second on 86.
A win or a draw would be enough for Atletico, while Barca need to beat the Madrid club to triumph by virtue of a superior head-to-head record, used to separate teams if they finish level on points.
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