Affeldt returned to the Giants in 2011 and posted a solid season, going 3–2 with a 2.63 ERA in 67 appearances, including 3 saves. In addition, he posted a career best WHIP of 1.151. Left-handed batters hit only .144 off of Affeldt in 2011. On September 8, 2011, Affeldt suffered a season-ending injury as he gashed his non-throwing (right) hand trying to separate frozen hamburger patties and underwent surgery to address nerve damage. After the season, the Giants picked up Affeldt's $5 million contract option for the 2012 season.