A big question this offseason for the Boston Celtics is whether coach Doc Rivers returns.  Although Celtics president of basketball operations Danny Ainge plans on Rivers to be on the sidelines next season, the coach was noncommittal on Sunday about his future in Boston.

Rivers spoke with the Boston Globe via text message on Sunday for the first time since the Celtics' season ended.  He was reticent to offer any hints about next season.

"Rivers said he needed to 'detox' after the season and apologized for being inaccessible to reporters," Gary Washburn of the Boston Globe wrote.  "But he would not give any indication whether he will be back for a 10th season although president of basketball operations Danny Ainge told the Globe last month that Rivers had planned to return."

Washburn also asked Rivers if he was still involved in the Celtics' decision-making process.

"I'd rather not say," Rivers replied.

Rivers, however, has been spotted during Boston's pre-draft workouts.  He also has three years and $21 million left on his contract.  If Rivers did decide to retire, he's not expected to string the Celtics along as the number of potential coaches decreases.

While there's heavy speculation Rivers is "seriously considering stepping down," his return could hinge on the futures of Kevin Garnett and Paul Pierce, according to Washburn.

Garnett and Pierce both could be out of Boston next season.  Garnett, 37, could choose to retire and the Celtics might decide to buy out Pierce's contract, according to Bleacher Report.  Garnett and Pierce are Boston's core — if they end up leaving, Rivers could elect to retire.

If his decision is tied to Pierce, the decision should come soon.  The Celtics must decide Pierce's future in Boston by June 30.  Rivers concluded his conversation by saying he intended to speak "soon" about his future in Boston.