Astros starting right-hander Lucas Harrell considers Bud Norris the team’’s No. 1 starter.

First-year manager Bo Porter isn’’t ready to give the ball to Norris just yet.

Porter said the Astros’’ top-of-the-rotation pitcher hasn’’t been set, while spots four and five will be a “competition” throughout the club’’s seven-week spring-training stay in Kissimmee and could extend into the regular season.

“You want to see who’’s going to take the bull by the horns and say, ‘’Look, I’’m showing you that I should be the opening-day starter,’’” Porter said at Osceola County Stadium. “”It’’s an honor to be an opening-day starter for a Major League Baseball team.””

Astros pitchers and catchers reported Monday morning, with some players arriving by 7 a.m.

Norris and Harrell will compete for the right to take the mound March 31 against the Texas Rangers at Minute Maid Park. The game marks MLB’’s 2013 season-opener.

Norris appreciates Harrell’’s support. But the four-year veteran went through a similar situation in 2012, battling then 33-year-old Wandy Rodriguez to take the ball on opening day. The elder Astro won. This year, Norris and Harrell — both 27 — will go head-to-head in Kissimmee.

“Lucas and I are going to go to work. We’’re going to battle it out and go to work, because that’’s our No. 1 priority,”” Norris said.

The back end

Porter is even less committal about the final two spots in the Astros’’ starting rotation.

Everyone from 33-year-old left-hander Erik Bedard — who didn’t report Monday, according to the Astros, but will pitch Tuesday — and former Rice standout Philip Humber will receive consideration for the roles.

Humber has been penciled in by many to hold down the four slot. After dealing with a wildly inconsistent 2012 — Humber threw a perfect game for the Chicago White Sox but posted a 6.44 ERA — the Tyler resident is open to whatever the Astros want from him.

“It’’s an organization that’’s going in a different direction and king of reshaping itself a little bit and so to be a part of that is kind of a different challenge for me,”” Humber said. “I’’ve usually been one of the youngest guys on the team and now I’’m one of the oldest.””