Manager Lloyd McClendon said Tuesday morning that Stearns had successful surgery at Arrowhead Hospital in Peoria on Monday.
After arriving in Arizona for spring training, Stearns experienced discomfort in his abdomen. McClendon said Stearns believed he was suffering a heart attack but after being examined by doctors the hernia was detected and surgery was scheduled.
McClendon said the team is still discussing internal options for filling in for Stearns as third base coach while he is recovering.
The 62-year-old Stearns is in his first season with the major league club after serving as the manager of Seattle's Triple-A affiliate for most of last season.