SAN FRANCISCO -- Three days before the start of camp, the Giants announced that one key backup will be missing from a spirited competition, and likely for the entire 2020 season.

Aramis Garcia, the front-runner to back up catcher Buster Posey on Opening Day, had surgery Thursday to repair the labrum in his right hip.

Garcia is expected to miss six to eight months.

Garcia's absence leaves three non-roster invitees battling to back up Posey: Tyler Heineman, Rob Brantly and Chad Tromp. Heineman, a switch-hitter who got into five games with the Marlins last season, seemed the likely competition for Garcia and now could have an inside track on the job.

The injury is a brutal break for Garcia, a 27-year-old who was set back by serious injuries in the minors. Garcia had hoped to get a head start on this year's competition by playing winter ball in the Dominican Republic, but he got hurt his first week there. A second opinion determined that he needed arthroscopic surgery to repair his labrum.

Garcia looked poised to back up Posey last season when the Giants did not re-sign Nick Hundley, but instead the organization added Erik Kratz at the end of camp and let the veteran bridge the gap to Stephen Vogt.

Vogt now is with the Diamondbacks, and president of baseball operations Farhan Zaidi said earlier this offseason that he was looking forward to giving Garcia an opportunity to prove himself. The Giants could add catching depth during camp, or wait and see which veterans get cut as rosters are set. Last year, they were able to add Kratz and Tom Murphy on the way out of Scottsdale.

As for the other non-roster invitee in camp, top prospect Joey Bart is not expected to be part of the competition to back up Posey. The Giants want him to start the year in Triple-A.

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"That could change, but as things stand right now, with the injury he had last year -- maybe if that had been different and he was further along it might be different -- but we still see him as someone we'd like to see get reps," Zaidi said. "It's a long spring training. A lot of things can happen. No matter what I say now, I know he's going to really impress people."