Vannett (illness) didn't participate in Thursday's practice, Teresa Varley of the Steelers' official site reports.
The severity of Vannett's ailment isn't known, but if he's able to return to practice Friday, there won't be much concern about his status for Sunday's game against the Jets. After playing 92 percent of the Steelers' offensive snaps and catching five of six targets for 40 yards in last week's loss to the Bills, Vannett will likely see his role get downsized Sunday with top tight end Vance McDonald (concussion) tracking toward a return. McDonald remains in the NFL's concussion protocol as of Thursday, but he practiced fully for a second straight day to begin Week 16 prep.