Harvin hasn't practiced much this week because of a rib injury, and Shiancoe is still working on a pulled hamstring that kept him out of the preseason opener.
"I think we'll do that with both of them and just give them a chance to get a few more days of rest and then get ready to go next week," coach Leslie Frazier said Thursday.
Receiver Greg Camarillo won't play because of a groin injury, which opens up playing time at the crowded position.
That list includes Camarillo, Devin Aromashodu, who was signed away from Chicago in the offseason, Jaymar Johnson, whose return skills could give him an edge, Juaquin Iglesias, and CFL transplant Manny Arcenaux.
Frazier said "nobody has really nailed down those spots yet," which is a big reason why the Vikings are choosing to keep out Harvin and Camarillo.
"If this were a regular-season game, things may be different," Frazier said. "But we really need to evaluate that position and when we talked about it, we said, 'You know what, we know Camarillo, we know Percy. We want to get to know these other guys much better so we can make the right decision.'"