JACKSONVILLE – Here's the understatement of the 2015 Jaguars offseason thus far:

Friday wasn't a good day.

There's no reason for sugarcoating when your first-round selection goes down with an injury in the first day of rookie minicamp – shoot, the first hour of rookie minicamp – and there's nothing quite like that scenario to cause a sunny day in a rosy offseason to dramatically shift tone.

We know now the prognosis for the edge rusher from the University of Florida. The No. 3 overall selection in the 2015 NFL Draft went down with a knee injury in a noncontact team drill midway through his first NFL practice. He sustained a torn anterior cruciate ligament injury in his left knee and is expected to miss his entire rookie season.

We know it's obviously not even close to ideal.

We also know there was no other real story Friday.

And we also know it obviously gave what had been a giddy, celebratory day around EverBank Field and the Florida Blue Health and Wellness practice fields a decidedly different and very unwanted feel.

The day began with Fowler smiling. And Jaguars Head Coach Gus Bradley was smiling, too. Of course. Fans lined the walkway to the practice field. They cheered Fowler and running back T.J. Yeldon and wide receiver Rashad Greene, and the noises had a familiar rookie minicamp energy.

Yes, Friday was going to be that sort of day. It was to be a day for brightness and shining and happy glowing. That's what Day One of a rookie minicamp is supposed to be.

Then, midway through practice, that changed. Fowler, who had been lining up on either side of the line of scrimmage at the team's Leo pass-rusher position in his first few professional plays of noncontact team work, rushed the passer in a similar non-contact play. As is often the case with knee injuries, he didn't appear to make serious contact with anyone at first. He was rushing against a tryout player, Watts Dantzler, a rookie from the University of Georgia. And really little usual happened at first. There was normal, minicamp-type contact. There was pretty much normal everything.

Except that Fowler's knee buckled – sideways, apparently – and then he was on the ground holding his left knee.

And then he was being assisted off the field by two trainers. He spent several minutes underneath the trainer's tent, then was carted to adjacent EverBank Field.

What happened next was what you'd expect. A sunshiny mood became something else. The stands and sidelines felt deflated. Speculation about the seriousness of the injury ran rampant on Twitter. Dantzler told reporters afterward he apologized to Fowler, and he said Fowler told him not to worry about it, that what happened was football. Dantzler told reporters, too, that fans were attacking him on Twitter. In this case, Fowler was right and those fans were wrong. It was football. Injuries happen. Even on the first day of minicamp.

An hour after the injury, Bradley spoke to reporters. As might be expected, his initial comments were about the minicamp in general, about rookies overcoming early-camp anxiety, about just what can be gained for the eight drafted players, nine undrafted players and 28 tryout players.

As also might be expected, the first question was about Fowler.

Bradley said he didn't know the extent of the injury, and that was about all a coach can say an hour after an injury. A few minutes later, he was asked about how the injury deflated the mood at practice.

"Any time (there's) an injury, it deflates you a little bit," Bradley said. "It's unfortunate but then you move on and you keep going. That's the message to the team. Like I said, it's hard for me to say what's going on right now. My mentality is it will end up being good and it will work out."

That's what a coach must say after an injury, even one to a Top 5 selection. And while we have focused here on how Fowler's injury deflated the first day, here's what it didn't do:

It didn't negate all the building that has gone on around this franchise, and it doesn't negate what has been a very good offseason. Regardless of Fowler's injury, the offseason was not a one-player story and the draft wasn't, either.

That's the truth, but the other truth is what happened Friday is exactly what every coach and general manager fear every time a team steps onto the field for an offseason practice. You fear losing any player for any duration, and you darned sure fear it happening to a young player around whom you're planning and building.

As of the original publishing of this story – late Friday afternoon – we knew few details. We know now that he is likely out for the season. We also know seeing Fowler helped from the field with little pressure on his leg was a sickening, sinking sight, and that there was no other real story on Day One.

And we darned sure know it deflated what had begun as a very different day.