LAKE FOREST – There is a purpose, a rhythm and a payoff for rookie minicamps, but in most respects they are the best of times and the worst of times for the players involved, and a bit of a riddle to be solved for the coaches who run them.

For the seven players selected in the recent college draft, this weekend it is pretty much all good.

Roquan Smith, James Daniels and Anthony Miller already have numbers they can keep, and fourth-round pick Joel Iyiegbuniwe almost certainly does, too.

Fifth-rounder Bilal Nichols, sixth-rounder Kylie Fitts and seventh-round pick Javon Wims will be given every opportunity to make the team — and one, two or all three most likely will.

If any of them don’t, they will either contract a mysterious injury that lands them on I.R., or be offered a spot on the Practice Squad.

For those seven, this should be fun, a warm-up and indoctrination for the real tests that will begin in Bourbonnais.

We now know there are 15 undrafted rookie free agents on the 90-man roster, signed as priority free agents over the past two weeks, and this is a category of players Ryan Pace has been unusually successful with unearthing occasional gems, including Bryce Callahan, Cameron Meredith and Roy Robertson-Harris, to name a few.

For this year’s dozen-plus-three, the best of times is they are on an NFL team for the first time in their lives and should be for at least the next couple of months, the worst of times because no more than one, two or maybe three are likely to make the final roster.

36 of these guys are college kids getting tryouts to become undrafted rookie free agents – in a big year two or three will be signed – seven are veterans and five are waiver-wire claims, all trying out for a chance to get to training camp and earn an extended audition. No more than a few of them might succeed.

This may be the extent of their NFL careers, but for a couple days they have a jersey and some Bears gear, and are playing on the same field Brian Urlacher did.

For more than 90 percent of them, their careers will last three days.

The riddle for Matt Nagy and his staff is: what are they looking for, and how will they know it when they see it?

“There [are] different reasons why guys come back to this situation. Maybe they had an injury. You just never know," said Nagy. “You’re just trying to make sure you see through everything and you don’t let anything slip through the cracks. That’s what we’re doing.

“So there will be guys that catch your eye, and when they do, you really want to go back and watch the film and see ‘was that real? ’That’s what we’ll do.”

20 years ago, Nagy was one of these guys, after a successful but less than blinding career as the quarterback at Delaware. I asked him if the arc of his playing career gives him a special affinity for these kids?

He actually seemed a tad emotional in his reply. “It does, it really does.

“It hits a spot with me, because I felt like I was one of those guys that just wasn’t tall enough, wasn’t fast enough, maybe not quite strong enough, didn’t go to that big school.

“I went to a I-AA school, so I refuse to let somebody slip by because of that. It’s not going to happen with me and I’m going to make sure that our staff understands that.

“There are kids in this building over here in the Walter Payton Center that practiced today that are going to get extra special attention because they’re not that guy. I can promise you that.”

One thing we learned today is that while we don’t know yet what kind of or how good a coach Nagy is going to be, he’s going to be an awfully hard guy not to like.

With that answer, it felt like the best of times.