San Diego general manager Jed Hoyer said Stauffer called the Padres head athletic trainer, Todd Hutcheson, complaining of pain around 3 a.m. PT Tuesday. Hoyer said that Stauffer had experienced pain earlier in the night and "was having trouble sleeping."
Hutcheson said Tuesday before the Padres played the Giants at AT&T Park that Stauffer initially did a self-diagnosis on the pain he was having in his abdomen on his iPhone, by using WebMD.com, before seeking Hutcheson.
Stauffer was then examined by Hutcheson, who quickly determined the pain that he was having wasn't related to food poisoning.
"It was pretty swollen; his whole side of the stomach was pretty tight," Hutcheson said.
Stauffer was put in a cab for the nearby St. Mary's Medical Center. He then had surgery around 9:30 a.m.
Stauffer will be discharged Wednesday. He will be on the team flight following Thursday's day game at AT&T Park.
Then will come a few days of rest followed by light workouts.
"After two weeks, we'll have a better idea," Hutcheson said. "He will be given a green light pretty quick [to work out], it will be three or four days to get comfortable and then it's riding a bike and gradually getting back to throwing.
"We've heard three weeks to eight weeks [of recovery time],"
In 2007, then-Blue Jays pitcher Roy Halladay needed 20 days of recovery time before he was pitching again. In 2006, Hayden Penn, then with the Orioles, needed two months to get back.
Last season, Milwaukee outfielder Corey Hart had an appendectomy on Aug. 2 and was back in the Brewers' lineup on Sept. 8 after a handful of Minor League rehabilitation games.
Stauffer, 27, tossed five scoreless innings in relief Sunday in Houston in a spot start for Kevin Correia. Correia was scratched from the start when he flew back to San Diego after his younger brother died in a fall Saturday.
The Padres placed Correia on the bereavement list Tuesday. Correia will make his next start Saturday at PETCO Park against the Dodgers.
Stauffer is 2-1 with a 0.39 ERA in 10 games this season, serving mostly as a long reliever. He opened the season with 17 1/3 scoreless innings of relief and helped to save the rest of the bullpen with a handful of long outings.
"He's been a huge part of our early-season success," Hoyer said. "For me, he's been about as valuable as anyone on the staff."
San Diego catcher Nick Hundley is hoping Stauffer has a smooth recovery and can rejoin the staff where he served an important role.
"I've been impressed by the way he's competed," Hundley said. "He's come into games where we needed him to throw well and he did. You can't expect more than he has given us so far."
Left-handed pitcher Cesar Ramos, who broke camp with the team, is expected to join the team. Ramos has a 3.86 ERA in six games with the Padres.
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.