Per the Mariners public relations twitter account, Hernandez was placed on the 10-day disabled list with right shoulder inflammation.
MLB Network's Jon Morosi added the expectation is Hernandez will be out for "at least" two to three weeks with the injury.
Hernandez has struggled in his last two starts, allowing 18 hits and eight earned runs in 8.1 innings.
Following Hernandez's start against the Tigers, Mariners manager Scott Servais told reporters Hernandez was battling a "dead arm" issue.
"He just didn't have much tonight," Servais said, per MLB.com's Greg Johns. "It's like dead arm as much as anything. He didn't have pain or anything like that. It's just nothing was coming out and he didn't feel good."
Johns added Hernandez will undergo an MRI in Seattle to determine the nature of the injury.
The 31-year-old Hernandez has a 4.73 ERA in 26.2 innings, and his 39 hits allowed this season are the most in Major League Baseball.
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