According to the website Arte Virtual FC, o Brasileirão, a.k.a Campeonato Brasileiro ou Brazilian League in FIFA, must be present in FIFA 18, even with the processes of several Brazilian players. This news has not yet been confirmed by EA Sports and it is still a rumor.
However, the rumor is not unfounded, as the agency MB Solutions, responsible for the FUT cards images of the athletes, has already took the photos of the players for FIFA 18, including Brasileirão players. Unfortunately, the image gallery for FIFA 18 is currently locked, but it's possible to see that Carlos Cesar picture with current season kit is in the gallery.
Since the exit of the Brazilian players from FIFPro, several athletes have sued EA Sports for improper use of their image. As if it could not get worse, other players have also refused to give in their image rights in last years. PES, from Konami, also faces similar problems, even having the Brasileirão official license from CBF. Thus, it is likely that players accepting the contract will have official names in the game, while the others will be represented in a generic way. Also, according to the Arte Virtual, Santos FC confirmed that received the players' image authorizations and that those interested should sign and forward to EA.
Most likely, EA should confirm the inclusion of Brazilian athletes at the Warner Summit on July 11 in São Paulo, Brazil or at Brazil Game Show on October 11, also in São Paulo. Until then we will hope that the rumor is true and that EA is investing in the Brasileirão again.