"I've been on the elevator for a couple of years," Phillips said.
Yankees manager Joe Torre has said that he'll put Giambi, 35, at designated hitter every now and then to give him a break from the field, which will land Phillips at first base.
Phillips is coming off a solid season at Triple-A Columbus, where he hit .300 with 22 home runs in 75 games.
"As far as preparation, it's the same," Phillips said of knowing the Yankees have specific plans for him. "Regardless of where I was every year, I am getting myself ready to play and play well. It's the same approach here. I think, more than anything, there's a comfort factor when you can come back to camp several times and [having been] around these guys for a while last year.
"[I do] the same thing I've done ever since I've started playing the games. My routine is to go out and prepare to play every day, and whether my name's in the lineup or not, you never know. Hopefully, [Giambi] stays healthy all year and I'll be ready when they ask me."
Even with Phillips' new role, there remains some uncertainty about how much he'll be needed to do for the Yankees this season. As a backup to Giambi, he'll see far less playing time then he has in the Minors. Then again, if Giambi gets hurt, Phillips will have to step right in and be an everyday player.
"We'll get him at-bats during the spring," Torre said. "The issue is how many at-bats we can get him during the season. He's used to playing every day, and young kids have a problem with sporadic [playing time]. It's an issue and a problem, but I don't know if we can solve the problem. Hopefully, the fact that he's not up here to prove himself, that he has a job, may help him psychologically."
For now, Phillips is happy to be with the big-league club and he doesn't seem to be taking anything for granted.
"I still don't look at it as there's a guarantee," Phillips said. "I am still fighting tooth and nail to get a spot. That's the way I look at it and that's the way it should be.
"[So far], I've had two really good days of work. I've gotten after it, and it's fun to be back out there on the field."