The Giants’ roster and on-field strategy are not the only aspects of the Farhan Zaidi administration that will blend the old and the new.

Nearly two weeks after the Giants hired Zaidi as president of baseball operations, he has not hired a general manager. In an interview Monday, Zaidi acknowledged the Giants might leave that position unfilled until next offseason, when they have a larger candidate pool.

Zaidi said his comfort with holdover assistants such as Jeremy Shelley and Yeshayah Goldfarb, plus the need to get moving on the 2019 roster, afford him the luxury of waiting to find the perfect fit for GM.

Zaidi also can lean on executive vice president of baseball operations Brian Sabean.

“There’s a very strong front office in place, obviously, to do the immediate business at hand as far as the major-league roster: free-agent signings, trades,” he said. “We have a pretty good infrastructure in place.”

Zaidi has not abandoned the GM search but said that learning the skill sets and philosophies of each candidate takes time. As the days drag on and the winter meetings draw closer, finding the right candidates and getting permission from their existing teams to interview is challenging.

“Being additive, bringing in the right person as GM and having that kind of structure, was the original vision,” Zaidi said. “But it also depends on identifying the right person, and potentially talking to and hiring the right person.

“We’re more focused on identifying the right person than the timing sensitivity.”

Even with a general manager, Zaidi would be working deep into the night now on two tracks: learning the hundreds of players on the Giants’ major- and minor-league rosters while engaging executives around the majors and player agents on trades and free agency.

Giants front-office holdovers began those conversations before Zaidi was hired, and Zaidi said they have “been great in moving along the things needing to be moved along. We’re in a good spot.”

The No. 1 question is whether Zaidi plans to trade Madison Bumgarner, which also is the No. 1 source of his “no comments.”

Zaidi would not say if he has apprised Bumgarner of his plans, although Zaidi acknowledged he has touched base with several players via text and phone calls. Common sense suggests Bumgarner would be one.

One notable conversation occurred last week, a face-to-face meeting with Buster Posey, who lives in the Bay Area full-time and is rehabbing his surgically repaired hip at a local facility. (Posey was walking normally as he attended the Willie McCovey memorial service at AT&T Park on Nov. 8.)

“He knows the organization, and he knows the players as well as anybody, being in the trenches,” Zaidi said. “He is at the point of his career where it’s all about winning and getting back to where this organization was in 2010 to ’14.

“Having that perspective, having accomplished all he has individually, and caring ultimately about the team’s performance, gives him a perspective that’s valuable for the front office.”

In other Giants news:

•Outfielder Heliot Ramos, the 2017 first-round draft pick, went 3-for-6 with two doubles for Santurce in his first two games in the Puerto Rican winter league. Ramos, who turned 19 in September, spent all of 2018 with low-A Augusta, Ga.

His stats (.245 average, 11 homers, .709 OPS) dropped precipitously from the previous year, when he dominated in short-season rookie ball, but the organization wanted to push him against older players in the South Atlantic League.

“To get through the season and not go back to short season is an accomplishment in itself,” Zaidi said. “We should start seeing real improvement projecting forward. I still think what he did was a success. The tools, the ability are all intact. He’s still someone to be excited about.”

•The Giants have four openings to add prospects to the 40-man roster Tuesday to protect them from next month’s Rule 5 draft. The list should be pitching-rich, starting with Melvin Adon, a right-hander with a triple-digit fastball. Adon walked three and struck out 21 in 121/3 Arizona Fall League innings.

Henry Schulman is a San Francisco Chronicle staff writer. Email: hschulman@sfchronicle.com Twitter: @hankschulman