This is a story about grass and hay.

The Bears are getting on the former, to paraphrase one of John Fox’s favorite sayings, on Tuesday. When they hold the first of three voluntary mini-camp practices at Halas Hall, the new Bears coach and his staff will get their first view of their players on the field.

Now for the hay part: the NFL Draft begins Thursday, and most of it is in the barn. Months of research by GM Ryan Pace and his staff has been completed, and little will change on the team’s big board between now and Thursday night.

In that sense, the two major activities at Halas Hall this week are disparate. Short of a major injury in the limited practices  — per NFL rules, teams are allowed on-field workouts and position-group drills, though there can be no contact or offense-vs.-defense scrimmages — little that happens on the field will directly affect who is drafted.

The Bears will watch some players switch positions and free agent signees line up alongside their new teammates, but won’t be swayed by three good days — or bad days — enough to change their draft philosophy.

Pace said he wanted to fill out his team via free agency to be able to draft the best available player.

At No. 7, that could be a receiver — Alabama’s Amari Cooper or West Virginia’s Kevin White or even Iowa offensive lineman Brandon Scherff. The GM has vowed to take an outside linebacker “if the right pass-rusher is there in the first round,” and could use help on the defensive line, where Washington nose tackle Danny Shelton believes he’ll be a good fit.

Team evaluations, and needs, typically don’t change in the few days leading up to the draft.

Rather, the Bears will learn more about their current players this week than they have since Fox was hired Jan.16.

“There are guys we saw, they have strengths and weaknesses in our book,” Fox said last month. “But until you are in those meeting rooms with them eight hours a day and watching them perform either in the weight room or on the grass, I think the good news is, sometimes when you come in, new there is new light.

“So guys don’t have preconceived ideas on them. You start from scratch. And that is the exciting thing about coming in new somewhere — both as players and as coaches.”

Their eyes will be fresh. Only two assistants — wide receivers coach Mike Groh and outside linebackers coach Clint Hurtt — were with the team last season.

With new faces come open minds. And, Fox said, an open competition.

“Obviously you’ve got to start somewhere,” he said. “In my experience in football, and really in anything, it’s not where you start the race, it’s where you finish it. But we have to start the race with some kind of lineup.”

That lineup doesn’t matter in April. What does is how the Bears’ players mesh with their new schemes, and coaches.

And no offseason training session could match the importance of Pace making his first draft with the Bears a successful one.

“In the draft is where you’ve got to make great decisions because that’s the core,” Fox said. “That’s how you develop the leadership that I’m talking about is, they’re homegrown, they’re your guys. They know your message.

“They know to carry the flag, so to string those together, obviously, in most people’s opinions, is how you do it.

“The art is stringing them together. Every one of those decisions is huge.”

Email: pfinley@suntimes.com

Twitter: @patrickfinley