Mahomes has averaged over 30 Rushing Yards Per game over his last 6 playoff games, including a couple of games where he was dealing with a foot injury that required off-season surgery.
In other words, Mahomes has a history of putting his body on the line rushing the ball in the biggest games of the year. With the Chiefs passing attack not as dynamic as it has been in past years, I like Mahomes to wrack up decent rushing yardage vs. this Pittsburgh team that is prone to allow QB runs.
Steelers allow the 4th most rushing yards to opponent QBs on the season, over 23 per game.