Each morning at 4:30 a.m., sometimes just a few hours after his playful 5-year-old son permits him to go to sleep, Bo Porter's alarm clock rings.

About 45 minutes later, the Astros manager fumbles for his set of keys that unlocks the gates at Osceola County Stadium in Kissimmee, Fla. In the depths of the barren ballpark, Porter runs sprints and lifts weights, partakes in a spiritual book-club reading and eats breakfast, all before the sun peeks out from beyond the horizon.

While it might be undesirable to the average person, it's a routine Porter adheres to on a daily basis during Spring Training. In fact, even during the dog days of Grapefruit League play, when most roster spots are secured and Opening Day is just a few squares away on the calendar, Porter won't be caught diverting from his rigid regimen.

So when asked if he was ready to put this year's extended Spring Training -- about a week longer because of the World Baseball Classic -- in the rearview and commence his first regular season as a manager, Porter wouldn't budge.

"I deal with the days as they come," the first-year skipper said. "Opening Day will be just like day 162."

Players and coaches approach the waning days of Spring Training in a variety of ways. Young players sweat out the last hours of the exhibition slate as the number of bodies in the clubhouse decreases. Guys unassured of roster spots savor every waking moment, aiming to enhance the impressions they've made. Veterans keep their eyes glued to their watches, waiting for the time to pass until the commencement of another regular season.

Porter's Astros are a young, inexperienced and eager bunch, itching to open the 2013 campaign Sunday night against the Rangers.

"We've been here a long time," said right-hander Alex White. "We're ready to get to Houston and get started. We're ready to play. It's certainly not anxiety; it's more excitement for us."

The enthusiasm in Houston's clubhouse has spread.

"That excitement level," said first baseman Brett Wallace, "the last two weeks it gets higher and higher, and that last week, you can see the finish line, it's so close."

Tigers designated hitter Victor Martinez has a different reason for counting down the days until Opening Day. The four-time All-Star hasn't played in a meaningful contest since Sept. 28, 2011, because of a torn knee ligament he suffered prior to last season.

"I've been looking forward to Opening Day for a while," Martinez said. "I'm just excited to come back and play again. I'm ready to play."

Despite no hits and eight strikeouts in his first 14 spring at-bats, Matt Tuiasosopo never wavered in his belief that he would make the Tigers' Opening Day roster. The 26-year-old learned Tuesday that he would begin the season as a reserve outfielder after flourishing at the plate over the past month. Still, Tuiasosopo refuses to look past the final few spring tilts.

"I'm thankful to be here. I don't have that luxury [of looking ahead to the regular season]," Tuiasosopo said. "Every day, I have to come in here and work hard. Whether I'm in the starting lineup or know I'm going to back up somebody, I approach it and attack it the same way. It's a long spring, but I'm excited because there are a lot of games and opportunities."

Curtis Granderson has had a different experience. He suffered a fractured right forearm in late February, which will likely keep him shelved until May, so he will stay behind and continue his rehab in Tampa, Fla., after the Yankees break camp. As he watches his teammates play out the Spring Training string, he can relate to their eagerness about taking the field at Yankee Stadium on Monday.

"It's just the number of days," Granderson said. "You're like, 'Man, this is another day, another day.' Once you're playing, you're into it. You want to go out there and keep playing because you're still trying to fine-tune yourself and get ready for Opening Day.

"It's just a matter of, 'We have a 3 1/2-hour bus ride today. Another one. We just had a night game that we're following up with a day game, and we have an early meeting beforehand.' The scheduling is so different than the regular season."

For Porter, the scheduling is even more abnormal. The Spring Training days might be winding down, but for the Astros manager, they still start early as ever.

"I just have a bunch of days that I wake up at 4:30," he said.