Then his world took a shocking turn for the worse.
Weiss' 3-year-old child, Brody, is hooked to a dialysis machine in an Atlanta hospital, his kidneys stricken with a potentially deadly infection of E. coli after a seemingly harmless swim at a water park.
"You don't see anything like this coming," the Braves' shortstop, taking a brief respite from the vigil by his son's bedside, said Wednesday night at Turner Field before his team's 10-6 loss to the New York Yankees. "It's a nightmare, but you have to deal with it."
Brody was still listed in serious condition, but his prognosis had improved enough for his father to leave the hospital for a few hours. After a news conference, Weiss slipped on his uniform for the first time since last Saturday's game at Montreal and took part in fielding drills and batting practice.
Weiss didn't hang around for the game, wanting to get back to his son.
"This thing has to run its course," said Weiss, who isn't sure when he'll be able to return to the Braves lineup. "We're still at a critical stage where things can change rapidly."
Weiss said his son seemed much better Wednesday. His eyes were brighter and he was able to talk with his parents. Doctors said the youngster will likely have to be hospitalized for at least a month.
"The most important thing is getting his kidneys operating on their own," Weiss said. "The doctors say there's a good chance that will happen in the next week or two. When that happens, we've turned the corner."
He called Brody his "high-maintenance child," which makes it even more painful to see him confined to a hospital bed.
"He's the one who has all the energy," Weiss said, a small smile curling on his lips. "He's the one who has the most chance of getting in trouble as he grows up. But he's a lot of fun. Everyone always asks about Brody, because there's usually a pretty good story involved. He keeps things very eventful."
Brody was one of at least eight children who contracted the bacteria while playing in a kiddie pool at White Water Park, a popular tourist attraction in the suburbs north of Atlanta. Weiss, his wife Terri and their three children were at the park on July 11, an off day for the Braves.
"You have to realize we live in an imperfect world," Weiss said. "I'm not here to place any blame. It's just a freak accident."