Buster Posey opted out of the 2020 season:
Posey posted the poorest season of his career in 2019. It was not terrible, but he is certainly no longer a star. The 2021 season will be the last guaranteed year of his current contract, and he may want to try healthy enough that the Giants pick up his option in 2022.
Apparently he and his wife have twin preemies. I have no problem with any player choosing family over playing this year. Kids don’t seem to be hit hard by the virus, but I wouldn’t take any chance with a newborn.