Bears QB Justin Fields practices in full

Bears quarterback Justin Fields took a major step toward being able to face the Packers when he practiced in full Thursday. If he does so again Friday, he figures to be in line to start the rivalry game at Soldier Field two weeks after separating his left shoulder.

Fields was able to do some things at full speed Wednesday, when he was limited in practice, quarterbacks coach Andrew Janocko said. On Thursday, he said the Bears were “trying to cut him loose” during practice.

“And [Friday], that’s when the determination is made,” Janocko said.

Fields’ full participation was surprising given that offensive coordinator Luke Getsy said earlier in the day the Bears would “play that thing out as the week goes, just like we did last week.”

Fields was limited in all three practices last week and couldn’t pass any of the Bears’ three checkpoints to face the Jets — he had to feel good, doctors had to clear him for game action and coach Matt Eberflus and general manager Ryan Poles had to sign off.

“It’s about him being able to be healthy, to protect himself, to do all the stuff needed,” Janocko said. “I think he just keeps getting better every day. That’s a good sign.”

In practice, he looked, well, normal.

“The thing about him is he looks like him,” Janocko said.

Running back David Montgomery agreed, saying Fields appeared to be his old self.

“It’s great to have him back,” Montgomery said. “QB1 — being able to have that guy back there and kinda make some plays and be who he is.”

For the second straight day, Fields looked comfortable in the portion of practice open to the media.

Backup quarterback Trevor Siemian missed his second straight practice with an oblique injury suffered during warmups in New Jersey. Nathan Peterman is next in line to start, with veteran Tim Boyle, signed Wednesday, as insurance.

The Bears waited until 90 minutes before kickoff to rule Fields out last week. Janocko said he was ready to play mentally, though not physically.

“If we would have made the decision for him to play, he was prepared to play,” Janocko said. “To me, that’s the most impressive thing.”

Instead, he had a front-row seat to watch Siemian in the loss to the Jets. Fields spoke to Getsy on the sideline and Janocko, who was in the coaching box, on the phone. They broke down what was going well for Siemian — and what wasn’t.

“It stinks that he wasn’t able to be out there because he needs as many opportunities, experiences as he can,” Getsy said. “But, obviously, we’re not going to risk it for just anything.”

Asked if one play stood out, Fields picked a subtle decision Siemian made. In the first quarter, Siemian checked down to running back Darrynton Evans.

“Just how fast he got to it was very notable to me,” Fields said.

Evans caught the ball only two yards past the line of scrimmage but turned upfield and eventually was tackled along the right sideline after 33 yards.

“All those moments are important — that he can gather from whoever’s playing,” Getsy said. “You went one hitch, he wasn’t there and he got right down to his checkdown. And it turned into an explosive [play].”

The Bears have been focused all year on trying to make sure Fields improves every game. Last week, that development came on the sideline.

Sunday could be different.

“The film-room sessions have been really good,” Getsy said. “He was locked in last week. He did a great job with that. He’s locked in again.

“We’ve just got to make sure we continue to progress, and he’s got to continue to develop. He’s got to continue to get these experiences so that we can continue to learn from them. He can grow.”