Adrian Wojnarowski of ESPN.com reported the sides have "reached an agreement in principle."
This comes after Wojnarowski reported on Aug. 20 that the Clippers offered Winger the job.
According to Wojnarowski, Winger was expected to report directly to Clippers president of basketball operations Lawrence Frank. Frank assumed the president of basketball operations position this offseason so head coach Doc Rivers could focus on coaching in lieu of roster building.
The Clippers also added Jerry West as a consultant in what has developed into an offseason of change in the front office.
As for Winger, he was an assistant general manager and provided team counsel for the Thunder. He also worked for the Cleveland Cavaliers for five years before starting his seven-year tenure with Oklahoma City in 2010.
The 37-year-old "has developed a reputation as one of the league's most respected young executives," Wojnarowski wrote.
Erik Horne of The Oklahoman pointed out it is not a new practice for other teams to hire Thunder assistant general managers as their new GMs. The Portland Trail Blazers hired Rich Cho in 2010 (now the Charlotte Hornets general manager), and the Orlando Magic hired Rob Hennigan in 2012.
Winger will take over general manager duties for a Clippers team coming off six straight trips to the postseason. However, they failed to advance past the second round any of those years and are now facing a new challenge after trading Chris Paul to the Houston Rockets this offseason.
Los Angeles still has Blake Griffin and DeAndre Jordan as cornerstones for the immediate future, but Winger will look to establish a culture of sustained success after his lengthy tenure with the Thunder.