"Look at what happened after that walk to him," Hernandez said.
The veteran right-hander retired nine of the final 10 batters he faced following Miller's RBI single as he pitched a season-high seven innings, allowing three runs and six hits in a losing effort.
"I was really happy to make it all the way to the seventh and kept the ball down," Hernandez said. "That's the main thing."
Astros manager A.J. Hinch was pleased to see Hernandez give his team a second consecutive seven-inning outing by a starter, following the lead of Collin McHugh on Tuesday.
"Early, he was battling himself and very animated on the mound and trying to catch his rhythm and get his pitches and then breezed through the middle part of the game and then finished with seven strong," Hinch said. "I think he probably had enough to go back in the tank. …
"I'm proud of the effort that Roberto gave. He got a lot of ground balls again. The two-out walk that came around to score is disappointing for him. All in all, you go into that game against that lineup -- sinkerball pitcher against a left-handed dominant lineup -- you get seven innings, three runs. That's a good effort."
Hernandez is 0-4 with a 3.32 ERA in his last six starts against the Mariners and is 0-for-3 with a 3.43 ERA in three starts at Safeco Field since 2010.
Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.