Hernandez won the AL Cy Young Award (2010) and two ERA titles (2010, 2014) over 15 seasons with the Seattle Mariners before becoming a free agent last off-season. He also earned six All-Star selections in Seattle.
The 34-year-old Hernandez signed a minor league contract with the Atlanta Braves in January 2020. He impressed during spring training, but the veteran right-hander eventually opted out of the pandemic-shortened 2020 season.
In his most recent MLB action, Hernandez posted a 1-8 record and 6.40 ERA in the 2019 campaign. He hasn't finished with an ERA below 4.00 since 2016, and his last All-Star appearance came in 2015.
Hernandez has a 169-136 record and 3.42 ERA in his MLB career.
The Orioles also announced Wednesday they have agreed to minor league deals with infielders Seth Mejias-Brean and Malquin Canelo, right-handed pitchers Dusten Knight, Konner Wade and Spenser Watkins and veteran left-hander Wade LeBlanc.