Entering Week 14, Bell ranked fourth among the NFL's high-volume runners in Rushing Net Expected Points (NEP). When factoring in what he's done through the air, however, Bell's been the best running back in the league -- he's added 45.25 points on receptions for the Steelers (again, prior to Week 14), which is 9 points better than the second-place Matt Forte.
Against the Bengals, Bell's Rushing NEP increased by over six expected points (roughly 46% of his season total), and his Reception NEP rose over eight points. In other words, he's going to still rate as the league's best runner according to our metrics.
And he's only 22.