Diggs, who led the National Football League in receiving yards going into Week 5, had just one catch for four yards during the Vikings' win over the Chicago Bears on Monday evening.
The Vikings defense should be at full strength after safety Andrew Sendejo returned to practice Friday.
Bradford has been hobbled by a knee injury since Week 1.
Bradford started in the Vikings' win Monday nights against the Chicago Bears but was unable to finish the first half due to his left knee injury.
With a career completion rate of 58.4 percent entering 2017, Keenum isn't an ideal option to lead Minnesota's air attack, but the Vikings at least know what to expect from him should Bradford be forced to miss extended time.
Jeremiah Sirles will likely get the start at left guard Sunday in place of the injured Easton. He had 10 past year, nine at tackle and one at left guard.