After a dud, Bill Lazor must find best way to use Mitch Trubisky

Bears coaches spent the bye week studying the team’s last four games against the Packers — all the matchups between coach Matt Nagy’s offense and coordinator Mike Pettine’s defense.

Quarterback Mitch Trubisky jumped out on film to offensive coordinator Bill Lazor, who didn’t coach in any of those games.

‘‘It just brings back to mind what all of his abilities are,’’ Lazor said Thursday. ‘‘Some of it is planned in the run game when he has played them in the past. And some of it is his ability in the pass game to move in the pocket and out of the pocket.

‘‘I think it’s pretty self-explanatory, but everyone knows what his abilities are — including the team we are going against.’’

Precisely how Lazor uses Trubisky will have a major effect on the game Sunday, which technically isn’t Nagy vs. Pettine anymore; it’s Lazor vs. Pettine.

For Lazor’s sake, it had better be an improvement on his first game as the Bears’ play-caller. After Nagy handed over the keys to the Bears’ sputtering, about-to-break-down car, Lazor’s offense set new lows. The Bears gained 149 yards — the fewest since Nagy was named coach — and only 32 in the second half in a 19-13 loss to the Vikings.

At least Lazor will have a new toy against the Packers. Trubisky figures to start Sunday, even though the Bears refused to announce it Thursday.

Trubisky won’t intimidate the Packers, who are 3-1 against him and have held him to a 76.3 passer rating the last two seasons, but he at least will give them a moving target. Trubisky averaged 5.2 yards per carry on 17 rushes in the last two seasons against the Packers.

Lazor said, ‘‘You’d probably be surprised at how little the calls have changed,’’ based on whether Trubisky or Nick Foles is starting. He’d be foolish, however, not to take advantage of Trubisky’s athleticism.

The threat of a bootleg seemed to help the Bears’ running game when Trubisky started the first three games this season. With the Bears’ offensive line broken down — left tackle Charles Leno missed practice Thursday with a toe injury — Trubisky must use his athleticism to improvise.

‘‘I think we’ve shown that throughout the year, as far as how much we run, how much we pass, how much we are in the shotgun, how much we’re under center, how much we move the pocket, how much we throw quick, try to throw deep,’’ Lazor said. ‘‘Those changes can be made pretty seamlessly, in my mind.’’

Nagy pointed to Lazor calling plays for Ryan Tannehill as evidence he knows how to use a mobile quarterback. While Lazor reportedly had a complicated relationship with Tannehill, Tannehill threw for more than 4,000 yards and ran for more than 300 in 2014, their lone full season together with the Dolphins.

Lazor’s use of Trubisky won’t be drastically different than Nagy’s was, given the conceptual similarities between the coach and coordinator. But it might be different at the most crucial times.

‘‘There can be a rhythm as to when you’re feeling a certain run, when you’re feeling a certain play-action, a screen, a movement outside the pocket, a shot,’’ Nagy said. ‘‘That’s probably the biggest thing. And maybe when you’re in the red zone and how your choices are there.’’