Sonderleiter did not play in Saturday's game against Penn State, but coach Steve Alford said the door is open for Sonderleiter's return.
"All I really know is that Sean called me Thursday and said he planned on talking to Coach and planned on quitting," Sonderleiter's mother, Kathy, told the Des Moines Register on Friday. "He's still a student. He wants to take care of that end of it."
The loss of Sonderleiter is Iowa's most recent blow. The Hawkeyes have only seven active scholarship players available. In the past two weeks, center Jared Reiner was sidelined indefinitely after foot surgery, and guard Mike Henderson and forward Nick DeWitz were ruled academically ineligible.
Sonderleiter, a senior, informed Alford late Thursday of his plan to leave the team.
"He's battling some personal family problems right now, and basketball's got to take a back seat to that," Alford told the Register on Friday. "We have to let that run its course, and how long that's going to take or what all the issues are, I'm not at liberty to say or even know at this time.
"We have to support Sean during this time and know that basketball is out of the equation right now."
Sonderleiter did not practice Friday. He could not be reached for comment.
Sonderleiter is coming off a 12-point, five-rebound performance in last Wednesday's 90-84 loss at Michigan. The points matched his season high.
He averages 5.4 points and 4.4 rebounds and leads the Big Ten in field-goal accuracy at 73.1 percent. The 6-foot 9 Sonderleiter has started the past five games, the last four as the replacement for Reiner.
"His numbers have really jumped since Jared's been out," Alford said. "It just came as a blind-side. Now we're trying to recover and see what's best for everyone involved."
Alford told the Register that he sensed a problem when Sonderleiter did not attend a mandatory film session Thursday.
"We were under the impression that he was sick," Alford said. "He arrived when the guys were lifting weights. I met with him at that time, and it was at that time he voiced some personal and family issues that he really needed to take care of."
Even Kathy Sonderleiter was surprised.
"You don't expect things like this; Sean hasn't emptied his heart to me," she said in an interview with the Register.
"This is between (Alford) and Sean. I'm a third party."
Alford said the team also was stunned by the news.
"There was a disbelief in the locker room," Alford said. "I don't know what the issues are, but I would think they're serious enough because he has a great relationship with his teammates and a great relationship with the coaching staff.
Alford told the newspaper that Sonderleiter had been under a lot of stress since last summer, when his sister died. Neither his coach nor his mother would elaborate.
School officials stressed that Sonderleiter was eligible to continue playing.
"Rumors are going to be out there; all we can do is say that this has nothing to do with academics or substance abuse," said associate athletic director Fred Mims. "That's as close as we're going to go as far as discussing it publicly.
"If people knew the pressure some of these kids really have, they would back off tremendously. Just think about some of your personal things that touch your heart -- that you don't want people to know about -- and maybe people will back off."
Sonderleiter was arrested and charged with possession of marijuana on July 3, 2002.
Alford told the Register that 6-7 Greg Brunner will start for Sonderleiter.
Little-used center Erek Hansen likely will see significant playing time, according to the newspaper.
Hansen, a 6-11 sophomore, has averaged 6.2 minutes in 10 games. He scored four points and blocked three shots in 15 minutes in an 88-82 loss against Illinois a day after Reiner's surgery.
Hansen has played only 62 total minutes.
"We have to be a team that perseveres through a very difficult set of circumstances that have been dealt our way," Alford said. "We've had the better part of two consecutive years where we haven't been able to create a break and become fortunate."