Query: Who announced on August 22nd they were leaving the Cubs prematurely? 
Context: In addition, long-time ace Carlos Zambrano was pulled from a game against the White Sox on June 25 after a tirade and shoving match with Derrek Lee, and was suspended indefinitely by Jim Hendry, who called the conduct "unacceptable." On August 22, Lou Piniella, who had already announced his retirement at the end of the season, announced that he would leave the Cubs prematurely to take care of his sick mother. Mike Quade took over as the interim manager for the final 37 games of the year.