Replays showed Braun standing on the top step of the Brewers dugout, loosening up by swinging his bat back and forth, when Segura walked up from behind and got hit in the face. Segura was immediately helped into the Brewers clubhouse.
Both Segura and Braun were out of Sunday's lineup against the Cubs. Braun departed Saturday's game himself after the eighth with a slight chest muscle strain.
Brewers manager Ron Roenicke updated reporters on Segura's status after Saturday's game.
"No concussion, no fracture but he was laid open pretty good. So a plastic surgeon stitched him up," Roenicke said. "He'll have some swelling tomorrow, I'm sure, so we'll see how quickly it goes down and how many days [out of the lineup] it's going to be."
"You never want to see something like that," Braun told reporters. "It breaks your heart a little bit. Obviously, it's never something done intentionally but whenever you're involved in a situation like that it puts life in perspective ... Thank God, from everything we've heard, he's OK. It could have been a lot worse."
Braun was facing the field on the top steps of the dugout, where he normally stations himself for his warm-up routine. Segura, who was batting second ahead of third-place hitter Braun, was coming up the steps behind him, and a TV replay showed the All-Star shortstop getting it on the right side of the head.
"It bugged me all game but it's one of those things you hope you can prevent. I know Braunny felt bad,'' Roenicke said. "[Jeff] Bianchi came in and did a great job for him.''
Segura is not expected to spend time on the disabled list. He was replaced by Bianchi in the lineup Saturday.
The Associated Press contributed to this report.