PHOENIX -- Slowly but surely, A's pitchers and catchers filed into Phoenix Municipal Stadium for reporting day Friday, trickling in with a light schedule in advance of Saturday's first official workout.

Only physicals were scheduled for this Valentine's Day, since pitchers and catchers are technically not required to show up to the facilities until Saturday. A handful, though, have already been working out at the park for several weeks.

That group includes position players, too. Josh Donaldson and Daric Barton were among the early arrivals, with newcomer Craig Gentry also making an appearance in the clubhouse Friday morning. The Texas transplant brought with him his old Rangers' bat bag, which was sure to be replaced by nightfall.

"We've had guys here for the better part of a couple weeks," said manager Bob Melvin. "I was out here yesterday and there were 20-plus guys here. Same type of atmosphere. Everyone is real excited about getting started."

Of the 55 players anticipated in A's camp this year, all 35 pitchers and catchers -- a group that includes 10 non-roster invitees -- are expected to be in attendance for Saturday's workout. Position players, meanwhile, are scheduled to report by Wednesday, with the team's first full-squad workout slated for the next day.

But not all will be healthy. Melvin announced Friday that relievers Sean Doolittle (right calf) and Ryan Cook (right shoulder) will be slowed in camp, though both are expected to be ready by Opening Day.

This marks Melvin's third Spring Training at the helm of the green and gold, including the second straight time his A's will attempt to defend their division title. Two years' running they've fallen victim to Justin Verlander and the Tigers in Game 5 of the American League Division Series.

In a sense, then, the A's have some unfinished business to address. But, "you have to separate every year," Melvin said Friday.

"You try to bring the successes you've had from previous years, and if you have a little bit of a chip, that's not a bad thing either," he continued. "As an organization, we've been good here, and we expect to be good again.

"We feel this is a nice window for us at this time, so everything we talked about in meetings and so forth has to do with the big league team and what we can do to make the big league team better. I think our expectations remain the same as they have the last couple years."

The A's mean serious business in a division that's widely improved, top to bottom. Texas, in particular, will run out an enviable lineup that added Prince Fielder and Shin-Soo Choo. An equally powered lineup resides in Anaheim, where the Angels seek better days with a strengthened pitching staff in tow. The Robinson Cano-led Mariners and the Astros have also improved.

But Oakland has upgraded, too, and the club's new talent -- headlined by Jim Johnson, Scott Kazmir and Gentry -- will be on display in game action beginning Feb. 26, when the A's christen the Cactus League schedule on the road against the Giants.

Oakland will play its first of 15 home games at Phoenix Municipal Stadium the following day against the Brewers, before moving its spring home to Mesa, Ariz., beginning in 2015.

Along the way, the A's will have several tough decisions to make.

Over the next six weeks, Oakland will have to fill out a rotation from a bevy of deserving candidates, along with a bullpen brimming with competition. A lineup will have to be created from a roster that's far from settled, particularly when looking at a crowded infield.

The A's Cactus League schedule will wrap up in Arizona on March 26, after which they'll travel back to the Bay for a pair of exhibition games against the Giants at AT&T Park. The A's will then host the Giants at O.co Coliseum for one final exhibition game.

All this leads up to March 31, when Oakland will open the 2014 season with a 7:05 p.m. PT game at home against the Indians -- likely as underdogs, despite recent success, in a stacked AL West.

"It's the way it is with us," Melvin said. "We don't get caught up in that. I don't read much of the forecasts. I think it's more about how we feel about ourselves. This team feels great about what we've done and where we're going, so the expectations we have for ourselves are more important than anything, whether everyone else thinks we're underdogs or not."