Both the Miami Heat, who acquired Chalmers in a draft-night trade, and agent Sam Goldfeder confirmed to The Associated Press that the guard left the program. Neither would divulge the reasons why the former Kansas standout, who hit the overtime-forcing jumper in the Jayhawks' win over Memphis in the national championship game five months ago, was asked to depart early from the resort in southern Westchester County, a short drive north of Manhattan, where the event was taking place.
"I'm in the process of investigating what exactly is going on," Goldfeder said.
The Heat said they also were investigating and declined further comment.
"The players were sent home for violating program rules," NBA spokesman Tim Frank said. "They will be appropriately sanctioned and will have to repeat the program next year."
Arthur, a 6-foot-9 forward who was chosen late in the first round by New Orleans, was traded three times on draft night and signed his rookie contract with Memphis in early July. The Grizzlies acknowledged Arthur "was sent home ... for violating program rules" but declined to give details.
"He will be sanctioned at a later date, and he will have to repeat the program next year," team spokesman Dustin Krugel said.
In addition to returning to the symposium in 2009, the former Jayhawks both may be facing a fine and suspension from the NBA.
Chalmers left Miami on Monday to begin the program, a four-day event which is required of all newcomers entering the league and focuses on issues such as life skills, handling finances, the importance of character and image, the difference between NBA and NCAA game rules, legal matters and dealing with media.
Chalmers is expected to compete for the starting point guard spot with the Heat when training camp begins later this month. He was drafted early in the second round by Minnesota and quickly traded to the Heat, who raved about his play in the Orlando summer league and signed him to a two-year deal.
"We really don't know all the facts yet, and I certainly would never comment publicly on any personal matter concerning any player I have ever coached," Kansas coach Bill Self said. "Beyond that, I can say that both Mario and Darrell were great to coach. They played a huge role in our success the past few years, in large part due to their unselfishness and the sacrifices they made for our program."