Defoe's spell in charge lasted just four months and six league games, ending two weeks before Woking's opening match of the new season against Sutton United. In a statement on the club's website, Brown said Defoe himself had never raised any serious issues directly with him during his tenure.
"Jermain's feedback was always positive, and he regularly expressed his enthusiasm and excitement for the season, both publicly and privately," Brown said.
"I can therefore appreciate the surprise and subsequent speculation surrounding his sudden departure.
"However, in recent weeks there had been feedback from across the club, including players, staff and other departments, regarding growing concerns."
According to Brown, that feedback prompted him to ask Defoe and assistant Paul Bracewell for a report "outlining the squad's current depth, recruitment targets and any operational challenges" so the club could provide appropriate support, but despite requesting it more than once, it was never received. A meeting involving the club's directors, the manager, assistant manager and head of operations was then scheduled to review preparations for the new season.
"Neither Jermain nor his assistant attended that meeting or that day's training session," Brown said, adding that he did not intend to speculate further on the striker's reasons for stepping away.
Defoe, who scored 305 goals in 763 senior appearances for clubs including West Ham, Tottenham, Portsmouth and Sunderland during a playing career that also brought 20 goals in 57 caps for England, previously worked as part of Rangers' interim coaching staff in 2021 and in Tottenham's academy before leaving in 2024 to pursue a full-time managerial role. He described his time at Woking as "an eye-opening managerial experience and one that will undoubtedly make me stronger for the next challenge in my career" when confirming his departure.
Brown, who took responsibility for appointing the former striker to his first permanent managerial role, said he had believed Defoe was "the right person to lead the club into an exciting new era" but acknowledged the difficulty of the transition from playing to coaching.
"As we have seen many times before, success as a player does not always translate into management and leadership," he said. "I sincerely hope to see him succeed in whichever direction he follows."