SAN FRANCISCO -- Giants catcher Buster Posey missed the first workout of Summer Camp last Friday for two good reasons: He and his wife, Kristen, were attending the birth of the identical twin girls, Ada and Livvi, that the couple was adopting.

Ada and Livvi were born premature at 32 weeks and will have to spend quite a bit of time in a neonatal intensive care unit. Given the fragility of their immune systems, Posey decided it would be in the best interest of his family for him to sit out the 2020 season.

"This ultimately wasn't that difficult a decision for me," Posey said during a Zoom call with reporters on Friday. "From a baseball standpoint, it was a tough decision. From a family standpoint and feeling like making a decision to protect our children, I think it was relatively easy."

President of baseball operations Farhan Zaidi and manager Gabe Kapler both expressed full support for Posey's decision. Zaidi, whose son, Jazz, turned 1 on Friday, held up a "We ❤️ Buster" sign during the call and said his toddler's birthday wish was a signed jersey from Posey.

"I think Buster is making an incredible and thoughtful decision for him and his family and the one that makes the most sense," Kapler said. "I'm actually proud to be here on this call, listening and supporting today."

Posey reported to Summer Camp on Saturday and was a full participant in workouts over the weekend, but he acknowledged that he was on the fence about playing through the COVID-19 pandemic in 2020. He missed three workouts over the first seven days of camp as he worked to finalize the adoption, which became official on Thursday.

Posey, who has another set of 8-year-old twins, Lee and Addison, said he and his wife have been trying to adopt for a few years. At one point, they were able to take home a baby for a few days, but the birth family ended up changing its mind.

"Anybody who has tried to adopt before knows that it's quite the roller-coaster," Posey said. "We knew about it for a couple of months. I was also cautiously optimistic that it would actually go through, having some of the previous experiences. It just so happened that the timing of their birth was the exact same day of our first workout."

Posey said he probably wouldn't have chosen to sit out the season if Ada and Livvi hadn't been born prematurely.

"There's no question, especially once games start up, this is going to be hard for me," Posey said. "I have had a little bit of time to think about that. Honestly, as a baseball player, there's such a satisfaction in going out and trying to accomplish something with a group of guys that become your friends over the course of the year or multiple years. Whether that goal is reached or not, by the end of it, there's satisfaction in knowing that you really put everything into it. I think I'm going to miss that the most."

Posey, a former National League MVP Award winner, is one of the highest-profile players to announce that he intends to sit out the 2020 season. At least eight other players have also said they have elected not to play: the D-backs' Mike Leake, the Rockies' Ian Desmond, the Dodgers' David Price, the Braves' Félix Hernández and Nick Markakis, and the Nationals' Ryan Zimmerman, Joe Ross and Welington Castillo.

Players who have a condition that makes them high risk can opt out for the season and still earn their full prorated salary. Posey will not be paid because his decision to not play was not influenced by a previous health issue, meaning he'll forfeit approximately $8 million of his prorated salary for this season.

Outfielder Hunter Pence said Posey has the complete backing of the Giants’ clubhouse.

“Everyone understands these are two lives that are high risk,” Pence said. “That’s a tough weight to put on your soul to be coming to play baseball and risking their lives. It’s a tough weight on everyone’s soul.”

Posey's decision leaves the Giants with no catchers on their 40-man roster with less than two weeks to go until they play their July 23 season opener against the Dodgers in Los Angeles. Zaidi said the Giants will continue to evaluate their internal and external options and will add another catcher to their player pool in the coming days to help spread out the load of handling the pitching staff.

Non-roster invitees Tyler Heineman and Rob Brantly, who have a combined 131 games of Major League experience between them, were viewed as the front-runners for the backup job. The Giants also have No. 1 prospect Joey Bart in camp, but they have expressed a desire to give him an opportunity to develop more before promoting him to the Majors. Bart, 23, missed time with two separate hand fractures in 2019 and hasn't played above Double-A.

"This is a tough environment to evaluate young position players that you maybe went into this situation thinking they needed more competitive reps at the upper levels, Double-A, Triple-A," Zaidi said. "We're having these workouts. There's live BP, and a guy takes a good swing and hits a ball 430 feet. That's all well and good, but it's not really a substitute for getting the 100, 200, 300 at-bats that you might be getting in Double-A and Triple-A, where you get a much better sense of whether a guy's capable of handling Major League pitching on a day in, day out basis.

"For Joey and for all the catchers in camp, it's certainly going to open up opportunity. It's hard to talk about specific timelines or exactly what that might mean at this point."

Non-roster invitee Chadwick Tromp and 2020 first-round Draft pick Patrick Bailey are the other two catchers in the Giants' player pool. Aramis Garcia, who underwent hip surgery in February, is rehabbing and isn't expected to return until late August at the earliest.

"There is no question that when players opt out around the league, that means their teams, their managers and their players have to adjust," Kapler said Thursday. "I think that's very obvious, and just leaving that aside, I think because of what we're up against right now, we are going to take a family-first approach to this. We will take it on as a responsibility to scramble as necessary."