The newspaper said the 42-year-old Maddux will announce his retirement Monday in Las Vegas, his hometown, on the first day of baseball's winter meetings.
The likely first-ballot hall of fame selection accumulated 355 victories -- eighth-most in major league history. He is a four-time Cy Young Award winner and an eight-time all-star selection.
He finishes 10th all-time in strikeouts with 3,371, despite striking out 200 or more in a season only once (1998). He ranks fourth in games started (740) and 13th in innings pitched (5,008 1/3). He compiled 17 straight seasons (1988-2004) with at least 15 wins and had back-to-back 20-win seasons in 1992-93.
Maddux ended 2008 with the Los Angeles Dodgers.
In November, agent Scott Boras told reporters Maddux was "doubtful" for 2009.
"As it stands now, he is not going to play," Boras said.