Yes, they will play against Nastic Tarragona in the playoffs. The other semifinal is Girona-Córdoba.
It´s no a basque team but the other direct promoted to Primera is Leganés, with basque coach (Asier Garitano) and lots of basque players, most linked to Athletic somehow: Bustinza, Guillermo and Galarreta (the 3 of them loaned from Athletic), Albizua, Eizmendi and Serantes (the 3 of them former Athletic players).