Chalmers, who as a starter has made key contributions in each of Miami's back-to-back NBA championship seasons, averaged 8.6 points, 3.5 assists, 2.2 rebounds and 1.5 steals per game in the recently completed campaign.
He will earn $4 million in 2013-14 before becoming an unrestricted free agent at the end of the season.
The 27-year-old University of Kansas product has posted career averages of 8.4 points, 2.3 rebounds and 3.6 assists over 366 games.
He tied a club record by making 10 three-pointers in a Jan. 12 win at Sacramento.
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