Luis Suarez will be out of action for "at least four to five weeks" after suffering a knee injury late in Barcelona's loss to Real Madrid.
Argentina superstar Messi agreed terms on a new deal until 2021 last month, with the club saying it would be signed in the near future.
Gabriel arrived in Valencia on Thursday, and Superdeporte reported that the 26-year-old will sign a five-year contract.
Getafe have signed goalkeeper Ruben Yanez from Real Madrid.
Sid Lowe details Diego Costa's desire to return to Atletico, and the FC crew discuss his relationship with Chelsea.
The ESPN FC panel assess how Luis Suarez's absence with affect Barcelona's formation and tactics as La Liga commences.