SAN FRANCISCO -- The Giants will have to make a lot of 40-man roster changes over the coming weeks. One player who wasn't on that roster has already been released.

Trevor Brown, a catcher who was Buster Posey's primary backup two years ago, was granted his release, per a source. Brown played 88 games for the Giants in 2015 and 2016 but spent the past two seasons in Triple-A.

Brown, 26, played 41 games for the River Cats this season, posting a .242/.331/.273 slash line. His highlight with the organization was the 2016 season, when he batted .237 and hit five homers as the backup catcher.

The Giants don't have much catching depth in the upper minors, although Aramis Garcia would begin the 2019 season back in Triple-A if Posey recovers from hip surgery in time for opening day and the team brings Nick Hundley back. Joey Bart, the organization's top prospect, is scheduled to begin next season with the High-A San Jose Giants.