A 30-year-old Vancouver native, Francis was a four-game winner in both 2008 and 2010 for the Colorado Rockies before heading to Kansas City for the 2011 campaign.
He picked up his fourth win this season on July 29 at Cleveland after eight scoreless four-hit innings on the way to a 12-0 rout.
He's 0-3 in four starts since, giving up 19 runs on 36 hits on 20 2/3 innings.
In two starts against Toronto, Francis has picked up a pair of wins while allowing only three earned runs on nine hits in 13 innings - a 2.08 earned run average.
The Royals are 3-7 in his last 10 overall starts.
On Wednesday, Brett Lawrie cracked the eventual game-winning home run in the bottom of the seventh, sending the Blue Jays to a 4-3 victory over Kansas City.
Jose Bautista crushed his major league-leading 37th home run, while Lawrie also tripled in a run. Edwin Encarnacion and Yunel Escobar added hits for the Blue Jays, winners in seven of their last 11 games.
Louis Coleman (1-3) absorbed the loss after surrendering Lawrie's blast.
Francis will be opposed by 25-year-old left Brett Cecil, who's winless in four starts since defeating Texas on July 29. He's subsequently gone 0-2 in August and has given up 12 runs on 13 hits on 27 innings against Tampa Bay, Oakland, the Los Angeles Angels of Anaheim and Oakland again.
Cecil was a 15-game winner in 28 starts with Toronto last season while racking up a 4.22 ERA in 172 2/3 innings.
The Blue Jays 5-5 in his last 10 starts.