The decision wasn't a shocker. Norris injured his hip flexor on May 31 and struggled after that. He sprained his knee against the Giants last Tuesday. The Astros called up Dallas Keuchel from Triple-A Oklahoma to make his Major League debut in place of Norris on Sunday.
Norris is 5-4 with a 4.81 ERA this season. From MLB.com:
"I've been trying to go out there and pitch at 80 percent and unfortunately I haven't been helping the team much," Norris said. "It's frustrating in that regard. I want to be out there every fifth day, but I understand that short term is more important than the long term and I have a whole second half to put it together to come back from this thing. I'm hoping it doesn't take a long time."