Not exactly sure, but guessing whomever trades for Fields is going to want to try to negotiate a contract extension after his rookie deal expires. With an extension acceptable to both parties, the Bears may be able to get a bigger return in the trade. So, the Bears likely contacted Fields' agent and OK'd for him to negotiate a deal with certain teams. Guessing that ATL is one of those teams. If so, the agent told Justin what is going down, and Fields then adjusted his Instagram accordingly. Trades can't be officially made until the middle of March, when the 2024 NFL season starts, but teams are gearing up for that date.