OAKLAND -- Following a disappointing offensive output last season, the A’s made it a priority to add some proven veteran hitters.

Oakland has since overhauled its infield, signing Jesús Aguilar, Aledmys Díaz and Jace Peterson, who will combine with returners Tony Kemp, Seth Brown and Nick Allen to give manager Mark Kotsay plenty of options. It appears one key decision has been made, with the shortstop position described as a platoon between Díaz and Allen.

“I think the way we’re going to start the season, the projection right now is to have Aledmys at short against right-handed pitching and Nick will play at short against left-handed pitching,” Kotsay said.

Both Díaz and Allen were in the lineup Sunday for the A’s 9-5 loss to the Giants at the Oakland Coliseum. Díaz started at third base and went 1-for-4 to bring his average to .300 for the preseason. Allen got the nod at shortstop and was 0-for-2 with a run scored. He is batting .265 this spring.

A career .266 hitter, Díaz spent the last four seasons with the rival Astros, winning a World Series last year. He batted .243 with 12 home runs and 38 RBIs in 92 regular-season games.

The A’s are counting on Díaz to help boost their run production after finishing last season with the second-fewest runs in baseball.

“Lack of offense last year, lack of ability to score runs, I think with Aledmys and Jace and Tony in that lineup, it helps us on the offensive side,” Kotsay said.

Allen will still get plenty of opportunities, both at shortstop and second base. The 24-year-old is looking to take a big step with his bat after hitting just .207 last year as a rookie.

“The way our infield aligns with Jace and with Tony, I think there’s an opportunity for Nick to play against right-handed pitching,” Kotsay noted. “You know how we do things. We pinch-hit late game. Nick provides us that ability to defensive replace because he is elite at shortstop defensively.”

Added Allen: “I think I’m just going to be prepared for anything, be ready to play when my name is called upon and go from there. So anything I can do to help the team win, whether it’s at short or anywhere else, I’m going to be ready to go.”

Aguilar will add some much-needed power at first base. The former All-Star hit 35 home runs in 2018, driving in 108 runs for the Brewers. The 32-year-old hit 16 homers last season and 22 the year before.

Peterson figures to open the season as Oakland’s starting third baseman, though Díaz will see time there as well. Peterson, 32, signed with the A’s after spending three seasons in Milwaukee, hitting .238 with 16 home runs and 70 RBIs.

Oakland still has a few roster decisions to make ahead of Opening Day on Thursday. With Manny Piña starting the season on the injured list, Kyle McCann and Carlos Pérezare vying for the backup catcher role, behind Shea Langeliers.

Cristian Pache, Conner Capel and Brent Rooker continue to battle for the final two outfield spots. And with four starting pitchers locked into the rotation, the last spot could go to JP Sears or Adam Oller.

The A’s will play one final preseason tuneup against the Giants on Monday night at Oracle Park in San Francisco.