Los Angeles Lakers star Kobe Bryant did not inform coach Mike D'Antoni that he left for Germany to have a medical procedure, according to the New York Daily News.
The team announced last week that Bryant left the country to have an unspecified medical procedure not related to his torn Achilles tendon.
Bryant reportedly only told longtime team trainer Gary Vitti that he was going to Germany for a second round of "Orthokine" for his right knee.
"Kobe not telling Mike D'Antoni tells you something about what Kobe thinks of coaches, and also Mike's status," one NBA head coach told the Daily News. "Now if that were Phil Jackson, I would think Kobe would have told him he was going."
Bryant also had the procedure in 2011. He said after the first time he had it that it made him "a lot stronger," and he was able to regain some quickness and explosion to the basket.
Other athletes have had the procedure, include New York Yankees third baseman Alex Rodriguez and golfers Vijay Singh and Fred Couples.
"Orthokine" is a process in which blood is taken from the problem area and spun in a centrifuge to create a serum that is then injected back into the problem area. It supposedly helps prevent cartilage degeneration.
Bryant has not been cleared by the Lakers to run or jump, and there is no timetable on his return from the Achilles tear. He was injured in April.