Manager Brian Snitker told reporters on Monday that Ynoa will be sidelined “a couple months” with the injury.
“That’s a tough one. He got frustrated after his outing [Sunday] and punched the seat in the dugout and broke his hand. It’s going to be a couple months that he’ll be down, then we’ll have to get him built back up. I hate to see that. The young guy was doing so well. That’s a big loss for us,” he told reporters, according to the Atlanta Journal-Constitution.
Ynoa allowed a season-high five runs on nine hits and two walks while striking out six over 4⅓ innings Sunday in the Braves’ 10-9 loss to the Milwaukee Brewers. He had surrendered just one earned run over his previous three outings.
Ynoa has impressed this season with a 4-2 record and 3.02 ERA in eight starts for a Braves team without All-Star right-hander Mike Soroka, who has been sidelined by an Achilles injury.
Soroka, who tore his Achilles tendon last August, had a setback last week and underwent exploratory surgery on Monday. There is no timetable for his return.
The Braves recalled right-hander Edgar Santana from Triple-A Gwinnett in a corresponding move.
The Associated Press contributed to this report.