La Blaugrana reportedly failed in a last minute deadline day move for the Spanish international as RB Leipzig rejected their €58m offer.
The Bundesliga giants were unwilling to lower their asking price from €65m with Jesse Marsch also unable to sign a replacement before the transfer window closed.
However, despite their frustration this summer, the Catalans will now return for Olmo at the start of 2022, according to reports from Mundo Deportivo.
Olmo is rumoured to be keen on going back to the Camp Nou in the coming months, after coming through the La Masia academy between 2007 and 2014, before joining Dinamo Zagreb.
RB Leipzig will not lower their previous asking price, with Olmo contracted to the club until 2024, but their deadline day agreement for Ilaix Moriba has put Barcelona in a stronger negotiating position.