"After September 15, Shakib will be available for selection," BCB president Nazmul Hassan told reporters after a board meeting.
Bangladesh's most prominent cricketer was banned for what the BCB called a "severe attitude problem".
He later apologised and made a passionate public plea to the board to reduce the punishment.
Shakib, who has played 34 Tests and 136 One-Day-Internationals, was accused of travelling to the West Indies to play in the Caribbean Premier League Twenty20 tournament without clearance from his board and was subsequently ordered to return to Bangladesh.
The 27-year-old had reportedly threatened to quit playing for his country and had an altercation with coach Chandika Hathurusinghe.
Shakib denied the allegation.
Tuesday's decision paves the way for Shakib to play in the home series against Zimbabwe in October-November.
Image: Shakib Al Hasan
Photograph: BCCI
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