Scottish Championship clubs have “voted overwhelmingly” to play a 27-match season – nine fewer games than normal.
And it has been confirmed that Hearts and Inverness Caledonian Thistle will feature in the division, after a proposal for an expanded Premiership failed to gain enough support.
The league announced the 10 second-tier clubs “approved” a shortened season, which will start behind closed doors.
A provisional start date of 17 October has been set for the 2020-21 campaign.
Hearts will mount a legal challenge against their demotion after finishing bottom of the top flight when last season was curtailed, while Raith Rovers were declared League One winners and join the second tier.
However, Partick Thistle have been relegated to League One and Falkirk denied promotion from the division after the reconstruction plans faltered.
Currently, only Premiership clubs are currently allowed to train before the division’s 1 August start.
The SPFL asked for assurances from Championship outfits that they could commit to a later start date with fewer games, to offset concerns about the cost of coronavirus testing and the practicalities of complying with return-to-training protocols.
If the correct protocols and arrangements can be put in place in the second tier, it is hoped they will be able to resume training in August or September, with a view to playing in the Betfred Cup at the beginning of October.
Hearts were last in the second tier in season 2014-15, winning the division a year after relegation.