Cain cut his right index finger while making a ham and cheese sandwich and was placed on the DL retroactive to April 24.
"It feels like a finger," Cain playfully told the San Francisco Chronicle on Thursday.
Said manager Bruce Bochy: "Barring any setbacks, he's good to go."
Cain, a three-time All-Star, is 0-3 this season with a 4.35 ERA.
Yusmeiro Petit, who started in place of Cain and gave up eight runs against the Pirates on Monday, will return to the bullpen for the Giants.