According to The Associated Press, the three-time Sprint Cup Series champion will announce his retirement at a Wednesday news conference, said an unnamed source "familiar with Stewart's plans." Clint Bowyer likely will replace Stewart as driver of the No. 14 Chevrolet for Stewart-Haas Racing in 2017, ESPN reports.

>> AUGUST 2014: Tony Stewart involved in fatal collision with other driver

>> SEPTEMBER 2014: Grand jury to weigh case of NASCAR's Tony Stewart

Stewart, described by the AP as "a lock for NASCAR's Hall of Fame," has 48 Sprint Cup victories and 582 starts in 17 years. He won championships in 2002, 2005 and 2011. 

But according to Motorsport.com, which broke the retirement news, Stewart has "not been the same person" in recent years. In August 2014, Stewart struck and killed Kevin Ward Jr., a driver who was walking on the track, at a race in upstate New York. Stewart faces a wrongful death lawsuit in the case. And in 2013, Stewart was injured in a crash in Iowa and missed one-third of the season.