Cardinal Francis George returned from Rome on Sunday, a day before Pope Benedict XVI announced he will step down at the end of the month for health reasons.
Colleen Dolan, spokeswoman for the Archdiocese, said Monday she was "surprised, had no idea" of the Pope's resignation. George himself had tenured his resignation a year ago when he turned 75 but is expected to stay in place for another year or 18 months.
In a statement, George said Benedict has "placed the will of God for the good of the Church before every other consideration."
"He has taught with clarity and charity what God has revealed to the world in Christ," he said. "He has handed on the apostolic faith; he has loved all of God’s people with all his heart. He has now shown great courage in deciding, after prayer and soul-searching, to resign his office at the end of this month."
The next pope will choose the leader of the Chicago archdiocese. George is expected to participate in the consistory -- the gathering of the college of Cardinals -- which will elect the next Pope.
In fact when Benedict was elected, George stood just several feet away on the Vatican balcony as his name was announced.
During a meeting of Vatican cardinals, Benedict said he lacks the strength to fulfill his duties. He will become the first pontiff to step down since the Middle Ages.
"After having repeatedly examined my conscience before God, I have come to the certainty that my strengths due to an advanced age are no longer suited to an adequate exercise of the Petrine ministry," he told the cardinals.
"In order to govern the bark of St. Peter and proclaim the Gospel, both strength of mind and body are necessary — strengths which in the last few months, have deteriorated in me to the extent that I have had to recognize my incapacity to adequately fulfill the ministry entrusted to me," he said.