Dan Wiederer: For Justin Fields and Bears offense, a shaky practice offers a timely lesson. ‘We need to have juice.’

CHICAGO — WARNING: The following material might prove jarring to sensitive Chicago Bears fans. We will offer everyone a moment to disengage if so desired.

For those who wish to continue, for those capable of handling a reality-check recap of an early-August football practice, well? Well, Wednesday morning was ugly for the Bears offense.

U-G-L-Y.

Mental mistakes. Sloppy execution. Worst of all, a lack of fire.

“We came out a little flat,” quarterback Justin Fields said.

That was at the start of an up-tempo padded practice at Halas Hall. And by the end of a workout that was the longest and most intense of training camp so far, the Bears offense was still lacking proper energy.

“The defense came out and they competed well,”