JACKSONVILLE – This was a day we won't soon forget.

Day 14 of Jaguars 2017 Training Camp began routinely, with Head Coach Doug Marrone making a nice bit of franchise history by opting to have the team practice in the Daily's Place Flex Field indoor practice facility for the first time.

This was notable. The franchise had been waiting for an indoor practice facility for quite a while. And the Flex Field, like so much that has been added around EverBank Field in recent years, is very modern, very functional and very cool.

But on Sunday, the Flex Field debut got overshadowed by one of the more memorable, newsworthy practices not just of Jaguars 2017 Training Camp, but in recent Jaguars memory. Of note:

*An injury to a starting wide receiver.

*A missed practice by the team's first-round draft choice.

*First-team reps taken by the backup quarterback.

*First-ream reps taken at middle linebacker by the player who was the starting middle linebacker last season but who had been the starting strong-side linebacker for the first two weeks of training camp …

Confused? Let's sort out the day, best as possible:

*The Injury. Although this was the last of the above-mentioned four events chronologically, we'll address it first because it was the scariest. Marqise Lee, a fourth-year wide receiver, sustained an injury to his lower right leg late in practice. Lee, who did not appear to take contact on the play, lay on the turf for several minutes with trainers, Executive Vice President of Football Operations Tom Coughlin, Marrone and wide receiver Allen Hurns gathered near. Trainers and Hurns lifted Lee into a cart, which took Lee from the field. "I know he was running a route," Marrone said shortly after practice. "I know he was looking to stop versus zone and I think he stopped. They're evaluating right now, so I'm just going to go in there after this and see where he's at." The team issued no further information about the injury, but initial media reports indicated the injury is not thought to be serious. If so, that's a relief for the Jaguars. Lee's having his best NFL camp, and the team needs his speed and dynamic play-making ability on the field. …

*The Absence.Rookie running back Leonard Fournette missed practice Sunday, and when the No. 4 overall selection in the draft misses his first NFL practice, it's news. Fournette, who rushed for 31 yards and a touchdown on nine carries in his NFL preseason debut against New England Thursday, missed Sunday with what Marrone said was a foot injury. "We're just being real cautious with it," Marrone said, adding that the injury "is something that has been kind of growing." Marrone added, "It was a nagging issue. And then the other day it was just sore, so we were like, 'Let's not take any chances. Let's take cautionary measure so it doesn't turn out to be something that could be worse.'"

*The Quarterback Reps. When Chad Henne took first-team reps Sunday, it marked the first time in '17 camp that a quarterback other than Blake Bortles took extensive work with the first unit. Bortles worked early in practice, and was intercepted twice – by linebacker Paul Posluszny and cornerback Tyler Patman. Henne, Bortles' backup since Bortles took over as the starter in Week 3 of the 2014 NFL season, looked crisp in three 11-on-11 periods and had particularly good rapport with wide receiver Allen Robinson. Marrone said Henne's reps were solely about resting Bortles' arm. "We were looking at the pitch count after yesterday, and we came in today and we felt like, 'Hey, let's just rest him [Bortles],'" Marrone said. "So it was basically for rest." Marrone was asked if the rest was related to the early interceptions Sunday. "Absolutely not," Marrone said.

*The Linebacker Reps.Paul Posluszny, the Jaguars' starting middle linebacker from 2011-2016, worked with the first team at middle linebacker in the team's base defense Sunday. This was news because the team had moved second-year linebacker Myles Jack from the strong side – where he played as a rookie – during the offseason, moving Posluszny from the middle to the strong side. That was how the duo lined up in the preseason opener Thursday. "We had Poz playing Mike, and Myles playing Sam," Marrone said of Sunday's practice. "I just want to make sure for our base downs we've got the best three players out there. We're just evaluating that and I just want to make sure." Asked if the move was an indictment on Jack's camp thus far, Marrone said "I wouldn't say that because he's probably coming off his best game." The Jaguars before Sunday worked Posluszny at strong, Jack in the middle and Telvin Smith at weak-side linebacker in base packages with Jack and Smith staying on the field in nickel situations. Could the Jaguars now use Posluszny in the middle with Jack at strong and Smith at weak-side and still leave Smith and Jack on the field in nickel? Stay tuned.