LAKE FOREST, Ill. -- Andy Dalton's starting job is safe -- at least for Week 1.

Chicago Bears coach Matt Nagy reaffirmed the team's decision to open the regular season with Dalton at quarterback when he announced on Tuesday that Dalton will not play in Chicago's regular-season finale at Tennessee because the veteran will be the team's Week 1 starter.

Instead, the Bears will start rookie first-round pick Justin Fields, who Nagy said should play two quarters on Saturday before giving way to third-stringer Nick Foles.

Fields will play with "some, but not all" of the Bears' starting offense, according to Nagy.

"I think it's going to be a good opportunity for Justin and then you know we'll be selective across the board for the other players as we go, but you're going to see a direction of more kind of like the old-school fourth preseason game for that," Nagy said.

"We just want to see him play hard, play well. The variables are different. He's not out there -- just like Andy hasn't been out here with some of those one receivers. So, all I want to see from him is just play a good game of football at the quarterback position and again keep the big picture in mind for all of us."

The push from fans to start Fields -- the 11th overall pick of the NFL draft -- over Dalton have intensified in the preseason.

Fields followed up an encouraging preseason debut versus Miami (175 all-purpose yards, two touchdowns) with a modest showing against Buffalo last week (9-of-19 for 80 yards and 46 rushing yards on four attempts).

Still, Fields' elite speed and uncanny knack for keeping plays alive outside the pocket has enthralled a Chicago fan base that has been bereft of a true franchise quarterback for more than 70 years.

"We feel really good with where Justin is at," Nagy said. "I would say for sure that for his level of where a lot of rookies are at this point in time, he passed that test.

"So that's a good thing. We know that. But now it's just growth for every one of these quarterbacks, Justin included. Everybody has a different story on how they get to the top. Every quarterback in this league has a different story. There's good examples of guys that have played from Day 1 as a rookie. There's great examples of that. There's also great examples of guys who haven't played from Day 1 and they've sat for a little bit. I'm talking about guys right now in the league. I'm talking about guys 10 years ago. We have to create our own of how we do it."

Dalton's best preseason moment occurred when he connected on a 73-yard touchdown pass to wide receiver Rodney Adams in the Bills game, but overall, the Bears' offense has stalled when Dalton has quarterbacked them the past two games.

To pin all of the Bears' offensive woes on Dalton, however, would be inaccurate.

The Bears have endured a slew of training camp injuries on their offensive line, including to one-time projected starting left tackle Tevin Jenkins, who recently underwent back surgery.

Dalton has also been without three key playmakers, receiver Allen Robinson, running back David Montgomery and tight end Cole Kmet, at certain points in preseason games.

Nagy has never wavered in his plan to start Dalton in Week 1, but he also has not ignored the reality that the Bears' starting quarterback job will eventually belong to Fields.

"We just feel really good about our quarterback room right now, I know that," Nagy said. "We feel really good, and that's a credit to these players that are in that room. It's a credit to our coaches that are coaching them, and now when we get an opportunity Week 1, as a unit, as a team, all three phases, we've got to put it together and go play Chicago Bear football."