SAN FRANCISCO -- While Brandon Belt's return to the Majors this season was all but inevitable, these certainly weren't the circumstances under which he hoped to come back to AT&T Park.

The highly heralded left-handed-hitting Belt, who was batting .337 with four home runs for Triple-A Fresno after hitting .192 in 17 games with the Giants earlier this season, joined the big league roster Thursday morning. He was joined by catcher Chris Stewart and shortstop Brandon Crawford to fill in for catcher Buster Posey, infielder Mike Fontenot and outfielder Darren Ford, who were moved to the disabled list.

When asked before Wednesday's game if he would consider promoting Belt from Triple-A to replace Ford and inject some much-needed offense into San Francisco's lineup, manager Bruce Bochy said he hoped to call up Belt in a situation where he would see more regular playing time. Unfortunately for Bochy and the Giants, that proved to be much sooner than expected.

"Right now, I don't know if we're in a position to be real sensitive to anybody's ability to play. Right now, there's a sense of urgency," Bochy said. "We need these guys. Hopefully they look at this as a great opportunity to show what they can do, and they'll all get some playing time."

None of the three callups were in the starting lineup Thursday afternoon against the Marlins, but Bochy insisted the club will need all of them to contribute in order to stay in contention. Belt, whose return was so widely expected that his nametag was never removed from his locker when he went back to Fresno, brings a big left-handed bat to the Giants' struggling lineup -- something desperately needed with Posey likely out of commission for the rest of the year, and Belt can play first base or either of the corner outfield spots.

Belt has been primarily used in left field for the Triple-A Grizzlies, though he has also played right field and occasionally at first. But more importantly, Belt said, his time in Fresno allowed him to clear up some mechanical and mental issues that plagued him at the plate during his short stint with the Giants this season. He admitted he was probably putting too much pressure on himself, and getting sent back down provided him an opportunity to "reset and start over."

"Everybody's goal is to get up here. It's terrible that it had to happen under these circumstances," Belt said. "I don't know whether I would have come up or not, but either way, it's not good to happen like this. I'm just happy to be here anyway, and hopefully I can do a little better than I did last time and have some good, productive at-bats."

Belt and Stewart were in Fresno when they received the news late Wednesday night. Stewart said he was following the Giants' extra-inning game online, saw Posey had been injured and instantly knew the club would have to add a player to its 25-man roster due to the severity of the injury.

"I saw the play, the video of the play, and it just looked horrible," Stewart said. "I don't know if I've seen anybody recover from something that drastic that quick. I figured something was going to go down. I didn't know what it was going to be. If something was going to happen, I hoped it was going to be me to come up."

And so the call came, and Stewart and Belt were told they would be promoted and picked up at 6:30 a.m. Thursday. With the players running on less than three hours of sleep, travel coordinator Mike Scardino's initial plan fell through, leading Scardino to drive down and pick up the duo himself.

But they eventually made it to AT&T Park, ready to contribute, albeit a little worse for the wear -- the night was so hectic that Stewart couldn't remember whether Fresno played a day or night game Wednesday, and Belt hadn't even spoken to Bochy before the rookie talked with reporters.

"It's been a long night. Not a lot of sleep, and then a pretty good little drive over this morning," Belt said. "A little short on rest today, but I'm sure I'll find some energy somewhere."