Bautista, along with Jason Momoa, has been a frontrunner for the role for a few weeks now, according to rumors. THR says he's been in the mix since last year. Other actors considered were Isaiah Mustafa and Patrick Wade.
Reports that Momoa was basically a "done deal" for the part surfaced online last month, but were almost immediately nixed. The popular theory is that Momoa was Marvel's first choice, but they couldn't work out a deal with the Conan the Barbarian and Game of Thrones star. That all sounds logical enough, but it certainly would contradict other reports circulating recently that claim to outline the way Marvel's casting process works.
Bautista joins Chris Pratt as the only two members of the cast officially on board. While rumors have maintained that Marvel is looking for a big-name comedic talent to take on one of the CG characters, Jim Carrey--one of only two names raised--has denied any talks have happened.