Diaz's father, Luis Manuel, was kidnapped over a week-and-a-half ago alongside mother Cilenis Marulanda. Marulanda was released on the same day, and efforts have been made ever since to ensure Luis Manuel's safe return.
According to Colombian outlet RCN, a significant breakthrough has been made in negotiations.
Luis Manuel's captors, the National Liberation Army (ELN) guerrilla group, have reportedly granted permission to the United Nations and the Catholic church - who are working alongside the Colombian government in negotiations - to facilitate Luis Manuel's return.
This will take place in an unknown location in La Guajira, near the Colombia-Venezuelan border, with reporters hopeful Luis Manuel could be returned later on Wednesday.
The ELN made contact with organisations such as the UN and the church on Wednesday, to set the conditions for Luis Manuel's release. The group claim his kidnapping was a "mistake", but have demanded the withdrawal of the Colombian military if he is to be freed.
Colombia's chief negotiator with the ELN, Otty Patino, told RCN that the liberation effort was underway. "We trust that it will be soon (…) there were surely problems, but the matter is on the right track,” Patino said.
Patino also assured that he does not believe there to be any financial motivation behind the kidnapping.
The development is a significant one, given that the ELN had promised to release the victim late last week, but with no changes as yet to Luis Manuel's situation. The father of the Liverpool forward has spent 12 days held hostage.
Diaz, meanwhile, made an impassioned appeal for his father's release, after scoring a late equaliser in Liverpool's match at Luton on Sunday.