He must have suspected Darrell Arthur wouldn’t fit into the “culture.” From ESPN.com’s Chris Broussard:

March Madness heroes Mario Chalmers (above) and Darrell Arthur were thrown out of the NBA’s rookie transition program on Wednesday morning after being caught in their hotel room with marijuana, according to several sources.

“They were sent home for violating program rules,” NBA spokesman Brian McIntyre said.

Sources said Chalmers and Arthur, who starred on the Kansas Jayhawks’ 2008 NCAA championship team, were also fined $20,000 apiece and will start the regular season on the suspended list. But McIntyre would not confirm that.

“We’re still looking into it,” McIntyre said. “Once we have all the details, appropriate sanctions will be taken.”

The players were caught by NBA security at the Doral Arrowwood resort in Rye Brook, N.Y., where 69 of the league’s rookies arrived last night for the four-day seminar in which coaches, referees and former players speak about adapting to the league. 

This seems rather unfair. I mean, presumably, one of the things they might have learned from former players is to lay a towel at the bottom of the door.