Dallas Mavericks star Dirk Nowitzki and Houston Rockets center Dwight Howard will become NBA free agents on July 1 after opting out of contracts Tuesday. German star Nowitzki, who turned 38 on Sunday, had a $8.7 million offer for next season to stay with the Mavericks, with whom he won the NBA title in 2011. Howard informed the Rockets he will decline a $23.2 million player option.
