The Giants claimed Kuhnel off waivers from the Brewers on Friday, Adam McCalvy of MLB.com reports.
Kuhnel hasn't pitched in the big leagues since early July due to right rotator cuff tendinopathy, but he's healthy now after completing a rehab assignment. The 31-year-old has posted a 4.84 ERA and 22:12 K:BB over 35.1 innings in the majors this season and will give the Giants some experienced bullpen help.