Bedard did pitch 3 1/3 innings of one-hit relief in Sunday's Opening Night win over the Rangers, earning the save. It was Bedard's first appearance out of the bullpen since 2004 with the Orioles.
"That's a big difference," Bedard said of pitching in relief. "I got lucky. I don't think I'll do any more of that. I'll probably just stick with starting."
Porter said he did not consider using Bedard in Friday night's blowout loss to the A's.
"If you're going to bring a guy out of the bullpen who's going to be in the rotation, you want them to get the full complement of rest," Porter said. "With Bedard starting on Tuesday, I didn't think that would be fair for him, having him pitch out of the bullpen [Friday] night and make a start Tuesday."
The Astros are Bedard's fifth Major League club. He has appeared in 193 games in the Majors, 189 of them as a starter.
Bedard, a native of Ontario, Canada, signed a Minor League contract with the Astros in January after going 7-14 with a 5.01 ERA last year with the Pirates.
"I thought it was a good fit," Bedard said of signing with the Astros. "They had a lot of young guys, and a lot of energy. I thought it would be fun to come here."
Bedard never thought about pitching in Triple-A this season.
"If I didn't make the team, I don't know if I would have gone to the Minors," he said. "Not too much fun. In my mind, I was going to make the team. That's what you've got to put your mind to doing. And I made it."
Bedard, 34, is the oldest player on the roster, born two months before Carlos Pena. Did joining the youthful Astros make him feel older?
"You've got that right," Bedard said. "Last year, I wasn't the oldest guy in Pittsburgh. When I came over here in spring, oh my God, I think I'm the oldest guy on the team. It makes you realize you are old in the sports world. When you're young, time doesn't go by fast. When you get older, how did it go by so fast? Mentally, you feel like you're still young."