Meredith was carted off the field after being tackled low by safety Johnathan Cyprien at the end of a 16-yard reception. Meredith's left leg twisted upon contact as he braced for the hit.
He was writhing in pain for a few minutes before being helped onto a cart with an air cast supporting his left leg.
"You feel bad, obviously," Fox said. "He's disappointed. He'll bounce back."
Fox said the team will know more about Meredith's status following an MRI.
The Bears quickly ruled Meredith out for the game, which they won 19-7.
Meredith -- a former undrafted free agent -- led the Bears with 66 receptions for 888 yards and four touchdowns last year.
He had missed a portion of the Bears' offseason program after tearing ligaments in his thumb, but the 6-foot-3 receiver returned for training camp and appeared to develop strong chemistry with starting quarterback Mike Glennon.
Losing Meredith for any extended period of time would be devastating for the Bears, who allowed receiver Alshon Jeffery to leave via free agency in the offseason. Chicago is also without veteran receiver Markus Wheaton, who is recovering from left finger surgery.
Bears long-snapper Patrick Scales also left Sunday's game with a knee injury, which the team believes is serious, according to Fox.
Cornerback Prince Amukamara played one series before leaving with an injured ankle. He was on crutches after the game, as was Scales.
ESPN's Jeff Dickerson and The Associated Press contributed to this story.