Oberlin, 21, was named in the senior Cameroon national team last week and looked set to make his debut under Seedorf.
His performances with FC Basel since joining the club from RB Salzburg in a €4m deal has attracted the attention of the Indomitable Lions coaching staff - and there's been a real sense of excitement over his future.
However, since being named in Switzerland's under-21 side, the Cameroon-born attacker has withdrawn from the 2019 AFCON qualification squad.
Oberlin was born in Yaoundé but moved to Switzerland aged nine and will still be eligible for his country of birth after the latest setback.
In nine caps for the U21 side, he's netted five times but an international tug of war is expected for the rising star, with the senior Swiss side monitoring the situation.
The 2019 AFCON qualifier against Malawi in Yaounde on 12 October will be Clarence Seedorf's first home game as manager of the African champions.