Aias, who arrived in a transfer from Watford FC, will undergo further medical evaluation before being eligible to join the Lions, the club announced Wednesday.
There is no immediate timetable for Aias to begin play.
The 23-year-old Brazilian was signed to a two and a half year contract with an option for another season a month ago.
Aias never made a first team appearance for Watford, but scored 23 goals in 74 appearances on loan with La Liga 2 side CD Mirandes over the last two years. The center forward broke through with Spanish side Granada after moving to Spain from his native Brazil and joined Watford in 2017, though spent almost the entirety of his spell with the club out on loan in Spain.