Karlsson was a late scratch for a season-opening 4-1 loss to the Golden Knights at T-Mobile Arena on Wednesday, when his wife, Melinda, delivered a girl the couple named Harlow Rain.
"The time (she was born) was the time of my life," Karlsson said.
Sharks center Joe Thornton said, "Fatherhood is the best thing in the world. We're all very, very happy for him."
Coach Peter DeBoer said Karllson would play in his usual pair with Brenden Dillon against Vegas.
"He makes a huge difference," DeBoer said. "But, having said that, if we don't play better than we did last game, two Erik Karlssons aren't going to help us win. He's going to help, but we've got to be better as a group."
In March 2018, when Karlsson was captain of the Ottawa Senators, he and his wife mourned the loss of their son, Axel, who was stillborn. Following his ninth season in Ottawa, Karlsson was traded to San Jose on Sept. 13, 2018.
"They've been through a lot, a lot more than anybody should have to go through," DeBoer said. "You can see the relief and excitement on their faces and when you talk to him here. It's a special moment."
Instagram from @erikkarlsson65: To my beautiful wife for doing everything in her power to bring our beautiful little baby girl in to this world, never have I met a more determined or stronger person than you. It hasn't been easy but after the rain finally our little rainbow arrived. Love you both more than I could ever imagine.
