Pitino said athletic director Tom Jurich ultimately made the decision to suspend the 6-foot-6 junior from Cincinnati. He added that Behanan is no longer living in the team dormitory, but he is still housed on campus and enrolled in classes.
"He had a number of suspensions last year, so this was not one thing," Pitino told ESPN.com. "It was many different things, and the AD and I just sat down and said he's got to get his head right and his life right before he plays another basketball game."
Pitino made the announcement at a scheduled news conference to preview Louisville's Red-White scrimmage on Saturday. The news came shortly after the defending national champion Cardinals were ranked third in the USA Today preseason coaches' poll.
Behanan, who averaged 9.8 points and 6.5 rebounds in 39 games last season, has been a two-year starter at power forward and was projected to start as a junior. Pitino said Behanan understands clearly why he's been punished.
"He knows this isn't something the university did to him," Pitino said. "This is something he did to himself. He's had multiple chances to do the right thing."
In Behanan's absence, sophomore Montrezl Harrell likely will start at power forward. Pitino had previously mentioned he would use the 6-9 Harrell at center so that he and Behanan would on the court at the same time.
Senior forward Stephan Van Treese is the only player in the starting lineup with experience at center. Pitino said the team will have to rely on freshmen Mangok Mathiang and Akoy Agau to fill in for Behanan.
Pitino also hinted that he could return to a four-guard lineup that was successful in the Cardinals' run to the 2012 Final Four. This time, it would be junior Wayne Blackshear playing power forward. Pitino said Blackshear was "a better 4-man than Kyle Kuric, and Kyle was pretty good."
Pitino said the team was preparing to be without Behanan for the long haul.
"It could be over as early as December, but knowing him, we gave him a list of rules to follow and he's already broken one of them, so I think it's possible [he'll be back], but not probable," Pitino said.
Behanan has faced discipline before. Last season, he was suspended for the Cardinals' preseason games and did not start the season-opening win against Manhattan. Pitino also banned the charismatic Behanan from talking to the media for almost the entire nonconference schedule. Pitino said at the time of the 2012 suspension that Behanan's immaturity led to his punishment.
Pitino had similar remarks Thursday when explaining that he wasn't expecting Behanan to work his way back onto the team anytime soon.
"I believe in going to the mat for our guys and going to the wall, and most guys, you give them chances and eventually they get it," Pitino said. "But I've had a few, not many, but a few, who just never get it. I'd say 90 percent do, but some don't. I'm not sure that Chane will get it."
Louisville received 10 first-place votes in the coaches' poll. Its first major test could come at No. 1 Kentucky on Dec. 28.
ESPN.com senior writer Dana O'Neil contributed to this report.