The right-hander would get a $1 million, one-year contract if added to Atlanta's 40-man roster.
Hernandez, who turns 34 in April, is coming off his worst season in the majors. King Felix went 1-8 with a 6.40 ERA in 15 starts for the Mariners and lost his place in the rotation.
Hernandez was among the best and more durable pitchers in the majors for more than a decade, a stretch that included six All-Star selections and the 2010 AL Cy Young Award. He was a huge crowd favorite at Safeco Field, with fans holding up K cards in The King's Court to mark his many strikeouts.
The two-time NL East champion Braves hold their first workout for pitchers and catchers on Feb. 13.