Heat guard Josh Richardson is out indefinitely after sustaining a partially torn MCL in his right knee, according to a league source.
Richardson injured the knee when he went up for a dunk and landed awkwardly during an informal workout with Heat teammates on Friday.
A timetable for his return was not known as of Friday afternoon, with the team running tests to determine the severity of the injury. But based on timetables for such injuries, Richardson could be back for the start of the season, with training camp beginning Sept. 27 and the regular season on Oct. 26.
According to Dr. Michael Glieber's sports blog web site, a minor, or grade 1, "MCL tear can take from a few days to a week and a half to heal sufficiently to return to normal activities, including sports. A grade 2 tear can take from two to four weeks to heal.
"A grade 3 tear usually takes from four to eight weeks to heal, unless it is associated with damage to the ACL, in which case the recovery time may be longer."
The University of San Francisco's sports medicine website says "on average, it takes six weeks for a MCL injury to heal. The initial treatment for most grade 1, 2 or 3 MCL tears focuses on reducing the pain and inflammation in the knee while immobilizing the knee to keep it stabilized."
Richardson, selected 40th overall out of Tennessee in the 2015 draft, averaged 6.6 points and 1.4 assists in 52 games last season, including two starts, and shot 45.2 percent overall and 46.1 percent on 3-pointers.
He emerged after the All-Star break, leading the league in 3-point shooting at 53.3 percent after the break and winning Eastern Conference Rookie of the Month in March.
Richardson is being counted on for a prominent role in the Heat's backcourt, along with Goran Dragic, Dion Waiters and Tyler Johnson, with Beno Udrih and Wayne Ellington also competing for minutes.
Richardson and most Heat players have been working out with Heat coaches at AmericanAirlines Arena. Two exceptions: Dragic, who has been in Slovenia, and Chris Bosh. Bosh has been working out in Los Angeles and as of Thursday, had not been cleared medically to return to the team.
