The Mariners are hoping that Hernandez, who is 4-4 with a 2.86 ERA in 10 starts, will miss only two starts. He is eligible to return June 12 as the move was retroactive to Saturday.
Hernandez didn't travel with the team to San Diego and was examined by Dr. Ed Khalfayan in Seattle on Wednesday morning before the roster move was made.
There's been much attention placed on the decreased velocity of his fastball, but Hernandez has remained a highly effective pitcher, if not a bit inconsistent. Opponents are hitting just .217 against him.
It is only the third time that the 30-year-old Hernandez has landed on the DL in his 12-year career, with his last visit coming during the 2008 season because of a sprained left ankle.
To fill his spot on the roster, the Mariners recalled James Paxton from Triple-A Tacoma. The left-hander, who is 12-8 with a 3.16 ERA in 30 starts for the Mariners over the past three seasons, will start Wednesday's game against the San Diego Padres.
The Associated Press contributed to this report.