Piniella told reporters (via the Chicago Sun-Times ' Gordon Wittenmyer's Twitter ) it was to be with his ailing mother.
"I didn't think my career would end this way, but my mom needs me home," Piniella said. "She hasn't gotten any better since I've been here. In fact, she's had a couple of other problems. To continue to go home and come back wasn't fair to the team, wasn't fair to the players. I'm going to miss it, no question about that. It was very difficult."
Here's the release from the Cubs:
Lou Piniella today announced he has elected to step down as manager of the Chicago Cubs following this afternoon’s game against the Atlanta Braves at Wrigley Field for family reasons.
“When I previously announced my intentions to retire at the end of the season, a primary reason for my decision was that it would allow me to spend more valuable time with my family,” said Piniella. “That time has unfortunately gotten here sooner than I could have ever expected. As many know, the several weeks since that announcement was made have been very difficult on a family level, requiring two leaves of absence from the club. While I fully intended to manage this club the rest of the season, a family situation at home now requires my full attention.
“As I said last month, I couldn’t be more appreciative of the Cubs organization for providing me the opportunity to be their manager. I wouldn’t trade this experience for anything in the world and I consider this the ultimate way to end my managerial career.
“I am thankful to the Ricketts family for their support – Cubs fans are fortunate to have an owner like the Ricketts family to lead this organization for the long-term. I also couldn’t be more thankful to Jim Hendry for bringing me to Chicago. We enjoyed a great deal of success together and I’ll always value the relationship we had during our time together. Thank you to Crane Kenney and the Cubs front office for your support throughout the years.
“I couldn’t be more appreciative of my coaches and training staff. They have been professional and supportive. And thank you to my players for the successes we shared and their efforts.
“Finally, to the Cubs fans, thank you for four wonderful seasons. You are the best, most deserving fans in all of baseball and it has been an honor to manage your ballclub.”
Cubs Chairman Tom Ricketts and General Manager Jim Hendry released the following statements:
“The Chicago Cubs are honored to have had Lou Piniella as our manager for the last four years,” said Ricketts. “My family and I respect Lou's decision to retire from the game he loves and thank him for his years of dedicated service. He is an icon in the world of baseball and we are grateful for his time with this organization.”
“Lou helped raise the bar here for this entire organization and for that we’ll be forever thankful,” said Hendry. “We understand he needs to be with his family and respect his decision to retire at this time. We salute his tremendous career and wish him and his family long-term health and happiness.”
One of only five skippers to win at least three Manager of the Year Awards, including 2008 with the Cubs, Piniella retires the 14th winningest manager in major league history. He enters this afternoon’s game with 1,835 wins in his near 23 big league seasons as a manager. Piniella is the first Cubs manager in more than 70 years to post a record of .500 or better in each of his first three seasons leading the club.
Piniella enters his final game with the Cubs with a 316-292 record in his three-plus seasons in Chicago. Only seven managers have won more games than Piniella in club history, while his .520 winning percentage is the best since Charlie Grimm’s .547 combined mark from 1932-38, 1944-49 and 1960 (minimum 500 games). Piniella is the first Cubs manager in 100 years to lead the club to consecutive post-season appearances in 2007 and 2008.
-- C. Trent Rosecrans
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