BY BARRY JACKSON bjackson@miamiherald.com Doctors found more evidence of blood clotting in Miami Heat forward Chris Bosh, derailing his attempted comeback, according to a source. The complication, believed to be in his lung, involved evidence of some continued clotting and is believed to be related to one of two previous blood clot episodes. Those episodes sidelined Bosh after the All-Star break each of the past two seasons. Though the complication is not considered life-threatening if treated, it requires medication and playing with it is considered unrealistic. Bosh was diagnosed with a blood clot that traveled from his leg to his lung in February 2015 and was diagnosed with a clot in his calf this past February. The Heat had gone into this week expecting to clear Bosh to resume his career this season, according to multiple sources briefed on the situation. But his clearance by the Heat always was contingent on Bosh passing his physical and no issues surfacing during a battery of Heat-administered medical tests this week. And when an issue arose in blood work this week, the Heat concluded he could not be cleared to return. A statement released Friday afternoon by the Heat said, “the Miami Heat and Chris Bosh, in consultation with team doctors and other physicians, have been working together for many months with the mutual goal of having Chris return to the court as soon as possible. Chris has now taken his preseason physical. The Miami Heat regret that it remains unable to clear Chris to return to basketball activities, and there is no timetable for his 9/23/2016 Evidence of continued clotting derails Miami Heat forward Chris Bosh's comeback attempt | Miami Herald http://www.miamiherald.com/sports/sp...103660572.html 2/5 return.” The NBA collective bargaining agreement forbids teams from announcing some medical information without a player’s consent. Blood clots are gel-like clumps of blood that can be dangerous, potentially life-threatening if not treated quickly with blood thinners or anticoagulants. There is a risk of playing sports while on blood thinners, because of the potential for bleeding if a player is cut.