The 25-year-old player looks set to return to the Chilli Boys having failed to establish himself at the Soweto giants.
Chippa's chief operations officer Lukhanyo Mzinzi revealed that they are close to concluding a deal with Pirates ahead of the January 2019 transfer window.
"Well, the deal is not done. We are still in the process of finalizing it," Mzinzi told Goal.
Maphanga has fallen down the pecking order in the left-back position at Bucs as the likes of Innocent Maela, Paseka Mako and Thabo Matlaba are preferred ahead of him.
As a result, Bucs are expected to loan him out to the Chilli Boys where he would provide competition for Tebogo Tlolane in the left-back position.
Maphanga has made only five appearances in all competitions for the Buccaneers since joining the club from the Chilli Boys in January 2018.
Chippa have also been linked with Pirates forward Meshack Maphangule, who has also found it difficult to cement his place in the team's starting line-up.
However, Mzinzi indicated that Maphangule is not part of the negotiations between the two Premier Soccer League (PSL) clubs.
"Meshack Maphangule is not part of the negotiations. We are only holding talks regarding Phetso Maphanga's services," he added.
Maphangule, who joined Bucs from Black Leopards prior to the start of the current campaign, is facing stiff competition in the team's attacking department.
The 27-year-old attacker is competing with South Africa internationals Thembinkosi Lorch, Vincent Pule and Zambian forwards Justin Shonga, and Augustine Mulenga.
He has made only two appearances in the league without scoring this season.