Greinke says he was changing sign sets, not signaling slider

Greinke allowed four runs, five hits in 4 2/3 innings with a walk and four strikeouts. He did not get a decision.

“That was just a bad pitch,” he said of the first home run, which put the A’s ahead 3-0. “The second slider I threw to him, I felt like I threw it good and he still hit it.”

Athletics manager Bob Melvin said the second-inning shot “felt like a 1,000-run homer at the time.”

Greinke has pitched five innings or fewer in each of his last five starts, including two in the postseason. But he did make the day easier on an Astros’ bullpen that had been taxed the previous three games.

The bullpen gave up five runs and six hits after not allowed an earned run in its first four postseason games. Blake Taylor, Cristian Javier and Enoli Paredes combined to allow only three hits in 3 1/3 scoreless innings before Ryan Pressly gave up a pair of runs in the ninth.

“It was very important for him to go that long. It allowed us to be a little more prepared,” Javier said.

Greinke, the 2009 AL Cy Young Award winner, is Houston’s most experienced starter on a staff missing Justin Verlander to Tommy John surgery and that lost Gerrit Cole to free agency.

Greinke felt soreness after his Sept. 29 start against Minnesota in a wild-card game that had been lingering. The right-hander, who turns 37 on Oct. 21, said there were no structural issues with the arm and that there were no issues on Thursday.