BOURBONNAIS — The introductory phase of training camp — two non-padded practices — has been unfulfilling for Bears rookie running back David Montgomery.

‘‘He’s at a point right now where he won’t even talk to me,’’ coach Matt Nagy said. ‘‘He’s so mad that we can’t put the pads on.’’

Really?

‘‘Naw, I’m just a really quiet person; I don’t really talk much,’’ Montgomery said with a smile. ‘‘My momma always told me, ‘You’ve got two ears and one mouth for a reason.’ So I [follow that advice].’’

Still, Montgomery can’t deny he’s particularly eager to move into the padded-practice phase Sunday at Olivet Nazarene University. In a 90-man camp where everybody has — or should have — fresh legs, he has been noticeably active, juking and shifting every chance he gets when he has the ball in his hands.

‘‘I can’t wait to get pads on,’’ said Montgomery, a third-round draft pick from Iowa State. ‘‘I want to show the team what I can do. I don’t think they really know what I can do. So I’m pretty excited to show the team I can actually play here on this level.’’

There is little live tackling in camp practices. But with pads on, there is plenty of hitting and an opportunity for Montgomery to show what he can do.

‘‘The physicality part, how physical I run,’’ Montgomery said. ‘‘How shifty I actually am. We all have pads on. You can just be shifty a little bit, but they’ve still got to tackle you. So now I get to play ball.’’

Nagy is eager to see it. The Bears brought in three new running backs with Nagy’s offense in mind: Montgomery, free agent Mike Davis and seventh-round draft pick Kerrith Whyte.

‘‘Going into the start of this camp, that running back position is what I’m probably most excited to see, just because you can’t see much in [organized team activities] on what they did,’’ Nagy said. ‘‘You can see mentally. You can see [what] they’re doing in their route tree. But now we put the pads on.’’

No player has been acquired specifically for Nagy’s offense like Montgomery. The Bears traded former Pro Bowl running back Jordan Howard to make room for Montgomery. And general manager Ryan Pace traded up 14 spots to select him with the 73rd overall pick.

‘‘[After] he left Ryan’s office, we all looked at each other and were, like, ‘We love that dude,’ ’’ director of college scouting Mark Sadowski said at a Bears100 convention panel in June. ‘‘Because he was better than we thought.’’

With the pads on, it will get that much more real.

‘‘You’re going to see that he breaks tackles,’’ Nagy said. ‘‘I mean, he was tops in college football in [broken tackles], and now you’re going against the big boys. And there’s some guys that can thump you. And he understands that; he lives for that. That’s what he wants to do. He’s a running back that plays with a physical style yet has the ability to do a lot of different things in the passing game.’’

Fellow running back Tarik Cohen likes what he has seen so far from Montgomery.

‘‘I know what type of player he can be,’’ Cohen said. ‘‘You never really know what’s going to happen, but the signs he’s shown are definitely very promising. He’s a strong runner, and he can also cut. His legs are very strong. He led the NCAA in broken tackles . . . so I’m ready to see him ball.’’

And once Montgomery gets into a competitive groove, he figures to start speaking up more.

‘‘He’s been talking,’’ Nagy said. ‘‘He’s quiet, but he has a sneaky confidence to him that I like.’’

Cohen echoed that sentiment.

‘‘He’s just quiet to you all,’’ Cohen said. ‘‘That boy is a jokester. He’s just in his shell right now. He’s going to break out soon.’’