PHOENIX -- A's pitchers and catchers reported to camp on Saturday, and are set to begin workouts on Sunday. But it appears the club will continue making more noise off the field than on it in the coming week.

While holding court with reporters on Saturday afternoon, manager Bob Melvin acknowledged there's a "definite possibility" the team will add more players before full camp opens Feb. 25.

Outfielder Yoenis Cespedes, signed to a four-year, $36 million deal this week, is presumably part of that mix once he gains a worker's visa and undergoes a physical. But he could also be joined by Manny Ramirez, who remains a strong possibility for the A's. Oakland is also trying to acquire Rangers reliever Koji Uehara via trade, and the A's have been linked with free agent Mike Gonzalez.

"There are probably some questions I have to shy away from, based on the fact that I'm not certain we're done on what the roster is going to look like," Melvin said. "But I think we've shown this offseason that we're not afraid to make some moves."

Meanwhile, Melvin has plenty of other things to focus on come Sunday, when 35 pitchers and catchers are expected to be in uniform for their first mandatory workout. Of that group, 11 represent non-roster invitees.

All were on hand for physicals at Phoenix Municipal Stadium on Saturday, and several position players also made appearances -- including infielders Cliff Pennington, Daric Barton, Chris Carter and Scott Sizemore, and outfielders Michael Taylor, Grant Green and Michael Choice.

Even more, according to Melvin, were going through workouts at the club's Minor League facilities.

"They're excited to get out ... start playing baseball and competing for jobs," Melvin said. "Everyone knows we've got a younger group here, a different mix than we did last year, and everybody sees the opportunity to go out there and show what they have to offer."

Over the next seven weeks, Melvin will have plenty of decisions to make, including but not limited to: filling out a rotation that currently has two spots up for grabs; creating an outfield from a surplus of candidates; choosing a first baseman; and naming a closer.

Cactus League play begins with a 12:05 p.m. PT contest against the Mariners at Phoenix Municipal Stadium on March 2, with action concluding in Arizona on March 21 against the Royals -- one day before the club flies to Japan to open the regular season against Seattle.

The A's are allowed to bring along 30 players on that trip and, once back in the States, to engage in a handful of exhibition games in the Bay Area. They will get to have even more on board before facing the deadline to set their 25-man roster. That gives the club plenty of time to answer the many questions that loom before April.

And Melvin, for one, doesn't plan on wasting much of it during his first spring as the club's skipper.

"Certainly you'd like to do things in Spring Training that kind of dictate and define your style," Melvin said. "We're going to try to get a lot of work in in minimal time, so that there's not a lot of standing around. For the work day, it's going to be about work -- and not standing around and waiting."