This would be awesome, especially if Andre Galvao also enters. The GP begins April 5 and airs on HDNet. While nothing is signed, it looks highly likely from everything I have been able to find so far, that Marcelhino will enter.
From Gracie Mag:
American Top Team coach Ricardo Liborio confirmed the likelihood Marcelo Garcia will sign with Japanese promotion Dream, which will host a 77kg Grand Prix this year. The tournament has already confirmed such high-profile fighters as Japanese idol Shinya Aoki, as well as a likely appearance from Andre Galvao, Marcelo’s rival from the days of their competing in sport Jiu-Jitsu.
"There’s a good chance. Nothing’s in ink yet, but there really is a good chance Marcelo will be in the GP," said Liborio to Portal das Lutas.