Shakir missed Tuesday's practice due to a rib injury, Maddy Glab of the Bills' official site reports.
The Bills haven't indicated that the injury is anything serious, but Shakir is jockeying for positioning in the team's receiver pecking order, so any missed time could prove costly. He's coming off a two-catch, 25-yard performance Saturday against the Steelers and seems to be slotted third or fourth on the Bills' depth chart heading into Saturday's preseason finale against the Bears.