Brobbey's contract expires in June, and he decided against extending his time with Ajax in favour of joining Leipzig on a free transfer next season.
He signed a contract through to 2025 back in March, but reports suggest he is now getting cold feet on the move after manager Julian Nagelsmann agreed to join Bayern Munich.
Brobbey, 19, has been at Ajax since the age of eight, coming through their academy system and broke into the first-team last season.
He is regarded as one of the best young strikers in Europe, and Ajax were keen for him to extend his stay at the Eredivisie champions.
But sources have told ESPN that the chance to work with Nagelsmann helped persuade Brobbey to sign for Leipzig. But with Nagelsmann now leaving, Ajax manager Erik ten Hag has confirmed the club are looking into whether it is possible to re-sign Brobbey from Leipzig before he has even arrived at his new club.
When asked on Thursday after their 3-1 win over VVV-Venlo whether he would like Ajax to explore a transfer for Brobbey, Ten Hag said: "I would like to. I indicated it to [director of football] Marc [Overmars], who is also working on it."
When asked whether the move was likely to happen, Ten Hag said: "I don't know if it is possible. I have talks with him about that but he hasn't spoken out loud he wants to stay here and I understand that since he just signed there.
"He's not even there yet and I don't know if Leipzig is open to that."