Santos elected to become a free agent Wednesday, Susan Slusser of the San Francisco Chronicle reports.
Santos cleared waivers after being booted off the Giants' 40-man roster, but he's opted to test out free agency rather than accept an outright assignment. The 26-year-old reliever has allowed five runs (two earned) over five innings in the majors this season and holds a 6.89 ERA and 11:11 K:BB over 15.2 frames at Triple-A Sacramento.