LOS ANGELES -- The Los Angeles Lakers do not yet know Dwight Howard's decision for next season, but the All-Star center made his feelings about Lakers coach Mike D'Antoni known before starting his offseason.

Nearly three weeks have passed since Howard had his exit interview with the Lakers and there's been barely a peep out of Howard since.

While he hasn't had anything to say to the press, Howard had a lot to say to Lakers general manager Mitch Kupchak back before the relative silence, however.

Howard was one of several Lakers -- Kobe Bryant and Pau Gasol being the most noteworthy -- to have an extended separate meeting with the GM after his exit interview with both Kupchak and D'Antoni, multiple sources confirmed to ESPNLosAngeles.com.

According to sources with knowledge of the situation, part of the discussion between Howard and Kupchak centered around Howard's frustration with D'Antoni -- particularly how the center felt marginalized as the coach looked to Bryant and Steve Nash for leadership and suggestions and discounted Howard's voice.

Every player was afforded the opportunity to meet with Kupchak individually after D'Antoni left the room, but few spent as much time as Howard and Kupchak did together. Antawn Jamison also had a separate meeting with Kupchak without D'Antoni present, but that was because of a scheduling conflict.

Kupchak left the meeting with Howard undeterred, telling reporters he was "hopeful" and "optimistic" that Howard would be back with the Lakers next season and beyond, yet there have been several developments in the last couple weeks that could have an effect on Howard's decision.

D'Antoni chose not to retain assistant coach Chuck Person, a Howard confidant, on his staff for next season. Also, Lakers assistant coach Steve Clifford, who was with Howard in Orlando for five seasons before both of them came to L.A. last year, has become a hot head coaching candidate, interviewing with Milwaukee and receiving interest from Charlotte.

One source described the potential departure of Clifford, coupled with the loss of Person as "removing the buffers," between Howard and D'Antoni, "which is a bad thing."

Howard has not conducted any interviews since the standard exit interview with the press and has only tweeted six times in that span -- one tweet containing a silly tongue twister joke, two tweets from a '50s-style theme restaurant, two sponsored tweet promoting contact lenses and one tweet on Mother's Day -- so there have been no public clues about what decision the pending free agent will make.