The Guardians signed Borucki to a minor-league deal Friday, Tim Stebbins of MLB.com reports.
Borucki will join his second team this season after making 21 appearances with San Francisco before being let go June 10. With the Giants, the left-hander posted a 4.94 ERA, 1.52 WHIP and 15:9 K:BB through 23.2 innings this season. The 32-year-old will report to Triple-A Columbus.