Soroka was the Braves' Opening Day starter in 2020. He suffered the season-ending injury against the New York Mets on Aug. 3.
Soroka, 23, had not begun throwing but was expected to return to the rotation this season. Now those plans are in doubt.
Manager Brian Snitker said Wednesday that Soroka will have exploratory surgery early next week in Green Bay, Wisconsin. The Braves will not have a prognosis for when Soroka might return until after the surgery.
"I hate it for the kid," Snitker said. "He's worked so hard and come so far and is so dedicated to get it back. I hate it for him personally to have this setback. And we won't know until after the surgeon goes in and sees exactly what's going on."
Soroka emerged as one of the foundations of the Braves' rotation in 2019, when he went 13-4 with a 2.68 ERA. The Canadian earned a spot in the All-Star Game and finished second in NL Rookie of the Year balloting and sixth for the Cy Young Award.
Even without Soroka, the Braves won a third consecutive NL East title and advanced to the NL Championship Series last season. Two other young pitchers, Max Fried and Ian Anderson, helped lead the rotation.
Fried was the team's Opening Day starter this season.
Snitker said a strong start by Bryse Wilson in Tuesday night's 5-3 loss to Toronto was an encouraging sign of the team's pitching depth. Wilson allowed two runs in six innings following his recall from Triple-A Gwinnett. Wilson was optioned to Gwinnett on Wednesday as right-handed reliever Chris Martin was activated from the 10-day injured list.
Martin said Soroka's setback was "obviously a huge loss."
"Hopefully he gets better and he can get back as soon as possible," Martin said.
Snitker said no one incident led Soroka to seek a medical opinion on his recovery.
"There was something that wasn't right, he could tell," Snitker said.
The Associated Press contributed to this report.