Jeffery was listed as a limited participant in Wednesday's practice, and the 26-year-old's absence the following day calls into question his availability for the Bears (0-2) in their road game against the Dallas Cowboys (1-1) on Sunday (8:30 p.m. ET).
"Just something we're monitoring," coach John Fox said, via the Chicago Tribune. "We'll see what tomorrow brings."
Signed to a one-year franchise tag tender of $14.599 million, Jeffery has reeled in nine receptions for 201 yards this season.
Jeffery collected 54 receptions for 807 yards and four touchdowns in just nine games in 2015. He has 261 catches for 3,929 yards and 24 touchdowns since being selected in the second round of the 2012 draft.