Dwight Howard is unlikely to re-sign with the Los Angeles Lakers, according to sources that spoke with ESPN's Chris Broussard.

The main reason for Howard's departure, should he leave, is Mike D'Antoni's system on offense.

Sources say the Dallas Mavericks and Houston Rockets are the favorites to sign Howard.

The Lakers can offer Howard a five-year, $118 million contract, while rival teams can pay just $88 million over four seasons. 

Howard hasn't completely ruled out the Lakers, but he did not enjoy playing with Kobe Bryant within D'Antoni's system.

Howard likes the idea of joining the Mavericks, where he would become the franchise player beside an aging Dirk Nowitzki.

The Rockets would be the best option for Howard, according to those close to him. But Howard has reservations about how he would fit in their perimeter-oriented system.

Howard will also meet with the Warriors in free agency.