From Chronicle Staff Writer Susan Slusser at Phoenix Muni

Yep, Alberto Callaspo might be on the smaller side for a first baseman – 5-foot-9 or thereabouts – but he will be Oakland’s first baseman when the team faced left-handed starters.

Manager Bob Melvin confirmed that’s the plan this morning (Melvin had been discussing this as a possibility since December) and he said that he has no qualms about putting Callaspo out there. Callaspo never had played first base before this spring, and he has not looked entirely comfortable there at times, but he does have good hands and the A’s believe he’ll continue to improve as he gets more accustomed to the spot.

Brandon Moss and Daric Barton will play first against right-handed starters, though Moss, at least initially, is more likely to get DH at-bats. I’m not sure how well-suited he will be for that, considering Moss’ high energy level; not every position player can handle regular DH duty, but Barton is certainly the superior defensive player, while Moss is the power hitter.

Melvin suggested today that he’s planning to stick with Josh Donaldson in the second spot in the lineup and Jed Lowrie third, though often that was reversed last year. Lowrie, a very good contact hitter, often swings early in the count when he feels he’s got a good pitch to hit – but that doesn’t always allow room for Coco Crisp to run. Donaldson loves having runners at second base, and he’s more apt to take a pitch or several to let Crisp steal second.

In addition, Lowrie is a switch hitter, like Crisp, and Melvin likes to sprinkle his switch hitters around the lineup to break up all the pure left-handers.

With Donaldson, a right-handed hitter, batting second followed by Lowrie, Yoenis Cespedes (right-handed) can hit cleanup rather than fifth when Melvin wants to go left-right-left-right.

Melvin, by the way, feels as if the homer Cespedes hit two days ago will go a ways toward getting on track. Sometimes that’s what it takes for a power hitter, he said.

In other news of the day, Nick Punto (hamstring) will not play today or tomorrow but he should be good to go for the Bay Bridge series.

Melvin said that Craig Gentry will DH in a minor-league game today and get six at-bats there, and Ryan Cook and Fernando Rodriguez will both throw an inning in that game. All three are on the DL; Cook and Gentry are expected back on April 5.

With a day off Sunday, No. 4 and 5 starters Dan Straily and Tommy Milone will split duties in Saturday’s game against the Giants at the Coliseum. (Scott Kazmir will start Thursday at AT&T, and Jesse Chavez on Friday.)

Melvin said that Jarrod Parker’s Tommy John surgery went well yesterday, but he has not yet spoken to Parker, who is unlikely to be able to pitch for the A’s again until several months into next season. Typically, second elbow ligament reconstructions require four months more recovery time than first surgeries, which means Parker is looking at coming back in about 16-17 months.