Alberto Callaspo is adding yet another glove to his bag this season. (Getty)

PHOENIX -- Alberto Callaspo spent Wednesday morning fielding grounders, which is nothing out of the ordinary for an eight-year Major League veteran who has served as a jack-of-all-trades throughout his career.

The difference this spring morning?

He wasn't at third base, where he has started 485 games, or even second, where he's started 230. Heck, he wasn't even at shortstop (21 starts) or in the outfield (nine). Instead, Callaspo was at first base, a position he hasn't appeared at even once throughout his professional career.

The A's are giving the 30-year-old Callaspo a look at first base this spring, one that appears to be set on fast forward. Manager Bob Melvin said Callaspo will again get work on the back field Thursday morning, and then there's "a decent chance" he'll make his debut there Friday against the D-backs.

The reason for adding another glove to Callaspo's bag is Oakland's search for another right-handed hitting complement to regular first baseman Brandon Moss, a lefty swinger. Callaspo, a switch-hitter, joins the right-handed Nate Freiman as someone who fits that bill.

Despite Callaspo's complete inexperience at first, the A's believe he can succeed there.

"There's nothing he does baseball skill-wise that suggests he couldn't," Melvin said. "I mean, he's got terrific hands, he's played the corner on the other side, as well as the middle. …

"As far as the skill-set goes, there's no reason he shouldn't be able to be a very good first baseman."

Third base coach Mike Gallego, who has overseen Callaspo's education at first, agrees. But, he said, the learning process -- no matter how quickly the A's speed it up -- is one that will take time.

Fielding the position shouldn't be an issue, with Gallego saying Callaspo will have "the most impressive hands that you're going to see at first base."

The biggest challenges facing him are the fundamentals of the position: footwork around the bag, taking throws up the line, getting off the line on those throws and staying on the bag.

Plus, there's the one instinctual difference between first base and every other fielding position on the diamond.

"Especially being a guy who has played second or third, your first reaction is to the ball," Gallego said. "First base, your first reaction, nine times out of 10, has got to be, first, away from the ball. So I think that's one of the biggest issues."

That's also why the A's are throwing Callaspo into the fire. After all, the extra work on the back field and tips from Gallego, Moss and others only go so far.

"The only way you're going to simulate that is getting into the games and doing it," Gallego said. "He's a Major League infielder. So I'm sure he'll figure it out over there in due time and get comfortable enough to play a more-than-adequate first base."

Then there's another aspect to consider: Callaspo isn't the only person who will need to adjust.

Moss, at 6-foot and 210 pounds, is a classic target at first base for other infielders. Freiman, at 6-foot-8, has the length to snag basically every ball thrown within his vicinity.

Callaspo, however, is 5-foot-9.

"I have no issues as far as his instincts," Gallego said, before adding with a smile, "Just as long as our infielders miss low, we'll be fine."