The Vikings gave up 125 yards rushing to Eddie Lacy and couldn't stop him at the end of the game when it mattered most last Sunday without defensive tackle Sharrif Floyd.
According to CBS Sports, Floyd missed the Packers game last week with a knee injury, but he is expected to return on Sunday.
Floyd didn't practice on Wednesday though.
Floyd is in just his second year with the Vikings. He has 34 tackles and 3 1/2 sacks this season.
Zimmer didn't know how much of a factor not having Floyd played in their struggles against Lacy and the Packers last week, but he does expect Floyd back on Sunday.
Zimmer made the remark at the end of his Wednesday press conference, but said the rest of the injury report would be issued after practice.
The Viking Age notes that Floyd suffered the injury during a freak incident at practice when he banged knees with another teammate.
The blog credits his emergence as one of the most improved areas of the Vikings defense under Zimmer this year.
"Floyd has not only demonstrated his value as a disruptive pass rusher, he's also shown that he can get after it when defending the run. Floyd has made a habit of blowing up screens, chasing down runners and generally creating mayhem all over the field.
Sharrif is definitely a big reason the Vikings have seen a marked improvement in their defense this year."