"I think there's been challenges," Fox said Monday. "I don't think that we've been two offensive lineups two weeks in a row. So I think considering all that, and really no different from a year ago, just at the quarterback position, I think I see improvement with us getting our feet wet a little bit at the receiver position, the tight end position as well as the quarterback position.
"Again, we're 3-6 -- that's reality. We've got to get better."
The Bears were playing without injured tight end Zach Miller (knee) for the first time, and backup Dion Sims was out with an illness. The offense played without guard Kyle Long (finger), and with center Cody Whitehair in his place while Hroniss Grasu played center.
Chicago also played after a bye week, while the Packers had the disadvantage of a short work week following a Monday night game. Yet the Bears were anything but sharp, with eight penalties.
"A lot's been made about the bye and this happened and that happened," Fox said. "I think, I mean even losing Zach Miller for the season, that was a little bit of a blow. Dion Sims not being available; those aren't excuses, those are just realities.
"To have a Pro Bowl guard not available (Long). Those are things that people deal with and not just our team but everybody's team. I wouldn't say by any stretch that we were at full strength because we had a bye week. I don't think that's reality, and bottom line is we didn't execute well enough."
For the second straight game the Bears offense had points taken away because of replay.
Fox on Sunday won a replay challenge but lost points because of it when it was ruled running back Benny Cunningham lost control of the ball just before hitting the pylon.
Fox correctly challenged the spot, thinking Cunningham didn't step out of bounds -- and he was right. The end result, though, was a lost fumble and touchback instead of a TD.
Fox said assistants watching for possible replays to challenge felt the same way he did about the play when he threw the red flag.
"Hindsight is 20-20," Fox said. "I probably would not challenge that if I were given the opportunity again. And we'll leave it at that."
There were absences that made a difference on defense, as well. Losing inside linebacker Danny Trevathan to a calf injury deprived the defense of its signal caller against Green Bay. The Packers ran for 160 yards on the Bears.