But, at the least, the records raise questions for hockey and professional sports of all kinds. Do team doctors communicate with one another about the care they are giving or the drugs they are prescribing? Do they demand to see a player before writing a new prescription? Are team medical records monitored and complete? How much information is shared among doctors, team officials and administrators of programs like the N.H.L.’s Substance Abuse and Behavioral Health Program? Can a hockey player, especially one paid to inflict and to absorb pain, continue a career with an addiction to painkillers? And what role does the league play in all this?

The N.H.L., teams, team doctors and substance-abuse program directors involved in Boogaard’s care all declined to discuss any of that.

The league, the Wild and the Rangers were given specific examples of the care that Boogaard received. Each released two-sentence written statements defending the care and citing the guidance of the league’s Substance Abuse and Behavioral Health Program.

None of the doctors mentioned in this article would comment. Neither would Dr. Brian Shaw or Dr. David Lewis, co-directors of the Substance Abuse and Behavioral Health Program that they founded in 1996 through the N.H.L. and its players association. They took on oversight of Boogaard’s care after he was placed in rehabilitation in 2009. Dr. Lewis is a psychiatrist on the staff of the Canyon, a rehabilitation center in Malibu, Calif. Dr. Shaw is a psychologist based in Toronto.

Little is known about their program, even within the N.H.L.’s league offices. The league, saying that privacy is paramount, has said that it does not know at any one time which players are enrolled in the program. Requests to interview the directors, even about the general parameters of their program or their ability to oversee three leagues with more than 1,500 athletes, have been routinely denied.

A Player Needing Help

Derek Boogaard was an unlikely N.H.L. star. When he was a boy, his limited hockey skills were offset by his size and his willingness to use his fists. Raised in small-town Saskatchewan, he grew into a feared 6-foot-8 brawler.

He became one of the most popular players for the Wild before signing with the Rangers for $1.6 million a season. It was a rare sum for an enforcer, someone whose role is like that of a playground bodyguard — to intimidate, and occasionally beat up, opposing players, whether to settle a simmering dispute or to excite the crowd.