Bass agreed to leave Dallas and sign with the Orlando Magic, the Eastern Conference champions announced Friday.
The Magic did not disclose terms of the deal, but a source close to the process told ESPN.com's Chad Ford it was a four-year, $18 million contract. NBA.com, which first reported the deal, said it included an escape clause after three years.
The Mavericks were hoping to re-sign Bass, but ran out of money and playing time with the acquisition of Shawn Marion. Coincidentally, Dallas is expected to soon get restricted free agent center Marcin Gortat from Orlando; paperwork is going through on an offer sheet that the Magic are expected not to match.
"Brandon is a physical, athletic frontline player," Orlando general manager Otis Smith said in a statement. "He will fit in well with our young core and we are excited to have him join the Magic family."
Bass is only 23, but he's been in the NBA for four years -- two with the Hornets, the last two with the Mavericks. He averaged 8.5 points and 4.5 rebounds over 19.4 minutes per game last season, almost identical to his numbers the previous season.
At 6-foot-8, Bass is a bit undersized for a power forward, but he's got a wide body and plenty of toughness. He also has a good midrange jumper and he made 87 percent of his free throws last season.
Information from The Associated Press was used in this report.