Barea had originally agreed to a two-year, $5.7 million contract, but he renegotiated after DeAndre Jordan reneged on his verbal commitment to the team.
Jordan's change of heart left Dallas with unspent money under the salary cap. Last week, guard Wesley Matthews also renegotiated his contract from $57 million to $70 million over four years.
In total, the Mavericks will pay Barea and Matthews $23.3 million more than they had planned. Jordan's contract would have been valued at $80 million over four years.
The 2014-15 season marked Barea's return to Dallas after a three-season stint with the Minnesota Timberwolves. Barea has played six seasons of his nine-year career with the Mavericks.
Last season, Barea played 77 games and averaged 7.5 points, 3.4 assists and 1.7 rebounds per game.
- Erin Flynn