The 44-year-old, Columbus, IN native has been competing in what's now known as the Sprint Cup (previously the Nextel Cup and the Winston Cup before it) since 1999, first with Joe Gibbs Racing and then with Stewart-Haas since 2009. He's won a massive 48 races, finished in the top ten a whopping 299 times, and has won the cup three times in his career – in 2002, 2005, and 2011. His last race win, however, came in 2013 in the FedEx 400 at Dover, before he broke his leg halfway through (and was forced to sit out the rest of) the season.
Controversy arose last season when he struck and killed another driver during a dirt-track sprint-car race, prompting him to sit out another few Sprint Cup races. Critics say he never bounced back from that trauma, or from the broken leg the prior season. He has yet to win a Sprint Cup race in the two seasons since, and missed out on making the Chase altogether this year.
In the anticipated announcement, Stewart is expected to confirm that he'll retire from competing full-time for Sprint Cup after next season, giving him one last go at winning the title and boosting his career record. His seat is tipped to be filled by Clint Bowyer, a 36-year-old Kansas native with eight race wins in the Sprint Cup and a second-tier Xfinity Series title already to his name. Bowyer currently drivers for Michael Waltrip Racing, but is reportedly to switch to HScott Motorsports for next year before taking Tony's place at Stewart-Haas. As for Stewart himself, expect him to continue on in a managerial capacity at the team, while running his other interests that include several dirt tracks across the country and an entire sprint-car racing series.
In related news, the startup Haas F1 team is also expected to announce its driver lineup later today. Sources point towards French driver Romain Grosjean (currently at Lotus) and Mexican driver Esteban Gutierrez (one of Ferrari's test drivers) to get the race seats at the new American grand prix racing team. Watch this space for updates on both driver announcements from the Haas teams once they're confirmed.