Groeschner was less concerned about Posey's fractured fibula, noting that it should heal normally. Posey, said Groeschner, underwent MRIs on his knee, ankle and lower leg to give Giants doctors a thorough look at the afflicted area. Groeschner said that Posey's knee is fine.
Posey, 24, was hurt during Wednesday night's 12th inning as he absorbed a home-plate collision with Florida's Scott Cousins, who scored the tiebreaking run in the Marlins' 7-6 victory. Florida completed a three-game series sweep of the Giants on Thursday with a 1-0 victory.
The Giants must confront the reality of trying to remain in first place in the NL West and defend their World Series triumph without their most important position player. Though the Giants rank last in the NL in scoring, Posey had lifted his batting average to .284 with a 13-game hitting streak.
"You just don't replace a Buster Posey," manager Bruce Bochy said. "He's not only your catcher handling a great staff, but he's also your cleanup hitter. Hopefully the other guys will step up. Right now we're not doing what we are capable of doing offensively, and they need to turn up the volume on their play."
The Giants weathered the absences of outfielders Cody Ross and Andres Torres earlier this season, and they'll remain without third baseman Pablo Sandoval for at least two more weeks. But though players have grown accustomed to such comings and goings, Posey's injury left them more somber than usual.
"When such a key part of your team gets injured, it's definitely a shock," right-hander Matt Cain said. "You just keep replaying the situation over and over. ... It's one of those things where we're hoping this can all go by quickly so he can go back to [being] Buster."
"This club has dealt very well with adversity," Bochy said. "We're still a very good ballclub."
For the immediate future, Eli Whiteside will ascend from his backup role to replace Posey as San Francisco's No. 1 catcher. The Giants purchased the contract of Triple-A Fresno catcher Chris Stewart to provide depth.
Whiteside is batting .185 in 15 games, including eight starts. Posey had started 41 of San Francisco's first 48 games.
"I'm not going to try to be Buster," Whiteside said. "He's our four-hole hitter and playing every day. I'm just going to go out there and do my best."
Bochy didn't rule out trying to obtain more help at the position.
"That's something that [general manager] Brian [Sabean] and I will talk about," he said.
The Washington Nationals, one of the few teams with a glut of catching, are known to be dangling Ivan "Pudge" Rodriguez and Jesus Flores. Rodriguez, 39, had a particularly strong game against the Giants on May 1, going 2-for-4, driving in two runs and throwing out fleet Darren Ford on a stolen-base attempt. Otherwise, quality catching is a rare commodity, largely explaining why Posey has been so highly regarded.
"There's nobody available out there," one Major League scout said.
In an attempt to compensate for the loss of Posey's bat, the Giants recalled first baseman/outfielder Brandon Belt from Triple-A Fresno. Belt, San Francisco's Opening Day first baseman who returned to the Minors after hitting .192 in 17 games, was hitting .337 with four homers, 21 RBIs and a Pacific Coast League-best .470 on-base percentage.
Bochy believed that Belt will be better prepared for a second stint in the Majors. The 23-year-old has addressed a mechanical flaw in his swing and played outfield more often to increase his versatility.
"He should have a little bigger sense of comfort," Bochy said. "I'll find ways to get him in the lineup to help us out."
The Giants also purchased the contract of infielder Brandon Crawford from Class A San Jose while placing infielder Mike Fontenot (left groin) and Ford (right ankle) on the 15-day disabled list.
None of the Giants accused Cousins of intentionally trying to steamroller Posey, who could not fully gain control of right fielder Nate Schierholtz's throw. But, asked whether he considered it a clean play, Bochy declined to give an unqualified endorsement. He instead suggested that rules be considered to protect catchers from bearing the brunt of such collisions.
"It's part of baseball," said Bochy, a former catcher. "I understand that guys run into catchers. I do think we need to consider changing the rules here a little bit because catchers are so vulnerable. ... Here's a guy [Posey] who's very popular in baseball. Fans want to see him play and now he's out for a while. So I'd like to see something considered where we can protect these guys a little bit more. They just don't have that protection to take a guy coming in full speed with that kind of force."