"We are very happy to be able to add an experienced veteran center at this stage of the season," Miami president Pat Riley said. "Ronny's energy will be a great addition and bolster our front line."
The seven-year veteran averaged 4.2 points, 3.2 rebounds and 1.1 blocks in 64 games -- 21 starts -- with New York in 2010-11. He was signed by the Wizards this season but was released after playing 56 minutes in four contests.
A second-round draft pick of the Lakers in the 2005 NBA draft, he has averaged 5.2 points, 3.8 rebounds and 1.4 blocks in 362 games, 90 of which were starts, with Los Angeles, Golden State, New York and Washington.