OAKLAND -- How long has it been since Alberto Callaspo last took grounders at second base?
"A long time," Callaspo said, smiling.
Oakland's new infielder, acquired from the Angels for Minor Leaguer Grant Green on Tuesday night, hasn't played there since 2010. He hasn't been a regular there since 2009. But his new manager, who just so happens to be the first manager he ever had in the big leagues in Arizona, isn't concerned about this.
"Because that's his natural position, that's where he started out," Bob Melvin said. "Now there is some uncertainty, obviously, because he hasn't played there a couple years, but he's always been a sure-handed defender. My talk with him this morning was that it doesn't matter where we play him."
Callaspo, 30, will mostly platoon with Eric Sogard at the position, though he can also spell Josh Donaldson at third base, too. No matter, he's happy to be joining a first-place club.
"I was surprised," he said, just minutes after walking into the clubhouse, fresh off a flight from Texas. "They took me out in the sixth inning last night and I was thinking, 'What happened?' Now I'm here and I'm trying to keep doing my job, playing 100 percent and help this team."
"He's excited about being here," Melvin said. "First day with your new club, flying in the morning, meeting everyone, it can kind of be a whirlwind. We're happy about having him, and it's probably a good thing we have an off-day tomorrow so he can get acclimated a little bit."
Callaspo remained on the bench on his first day in Oakland, with Sogard drawing the start against Toronto knuckleballer R.A. Dickey, but he got a crash course at second base prior to the game, fielding grounders from infield coach Mike Gallego.
It's Callaspo's ability to get on base, though, that really sold the A's, who are on the hunt for a second consecutive American League West title.
"Switch-hitter, good from both sides of the plate," Melvin said. "I think one of the most difficult guys to strike out. You can hit and run with him. There are a lot of things you can do with him. So it is an upgrade for us. We feel good about having him here. We feel like he's a piece that fits real well for us."
"I'm just going to try to do something, try to help the team," Callaspo said. "If there's something they need from me, I'm going to try and do it."
With Callaspo on board, the A's opted to designate Adam Rosales for assignment. He was hitting just .193 in 50 games while serving in the same role Callaspo will now fulfill.
Oakland has 10 days to trade, release or pass Rosales through waivers, the same thing that happened to him a few weeks ago when he was initially designated to make room for Green.
"We still feel like he might be our best defender at shortstop in the organization," Melvin said. "It'd be nice to be able to keep him. We'll see if that's the case."
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.