The deal signed Friday could pay Howard as much as $4 million if he meets certain incentives. The two sides reached agreement on the contract Wednesday night.
Howard was acquired in a trade with the Dallas Mavericks on Feb. 13, but he played in only four games before tearing a ligament in his left knee on Feb. 22.
Howard had surgery in mid-March, with an expected recovery time of six to eight months. Agent Derek Lafayette says Howard is "ahead of schedule" but declined to say whether the forward will be healthy in time for training camp.
Howard has averaged 15.3 points during seven NBA seasons.