Pienaar, 29, picked up the injury during Spurs' pre-season friendly against Athletic Bilbao on Saturday, and underwent surgery early Tuesday.
"Following scans and consultation with an independent groin specialist, Steven Pienaar underwent groin surgery this morning," Tottenham announced on the club's official website.
"(He) is expected to be sidelined with the injury for up to six weeks."
Pienaar joined Spurs from Everton in January on a four-year contract.
Source: AFP
Source: AFP