Dante Fowler Jr. didn't miss a game in three years of college.
The former Florida star likely will miss his entire rookie year in the NFL.
The Jacksonville Jaguars defensive end, the third overall pick in last week's NFL draft, is likely out for the season after tearing a knee ligament during his first practice.
Fowler tore the anterior cruciate ligament in his left knee during rookie minicamp Friday. ESPN first reported the extent of the injury.
The injury looked serious live and appeared even worse in video replays. Tests revealed the extent of the damage.
Fowler's knee buckled during an 11-on-11 drill as he engaged right tackle Watts Dantzler. Fowler dropped to the ground, grabbed his leg as he rolled from side to side and eventually got helped off the field. He was carted to the locker room.
"I went to apologize to him and he was like, 'You're good, man. It's just football,'" Dantzler said.
Fowler was the first non-quarterback selected last week, taken by the Jaguars after quarterbacks Jameis Winston (Tampa Bay) and Marcus Mariota (Tennessee).
The Jaguars were counting on Fowler to be a centerpiece of the defense for years. They had expected him to be a Day 1 starter, meaning he would replace 33-year-old veteran Chris Clemons.
Now, though, it's unlikely he will play in 2015.
Although players have returned from torn knee ligaments in seven months' time, the Jaguars would have to be in playoff contention to even consider bringing Fowler back so soon. The franchise, which is nearing the end of its ground-up rebuild, has won nine games over the last three years.
Fowler's injury happened during a two-day camp that featured eight draft picks, nine first-year players and 28 workout players trying to get a shot at the NFL. Jacksonville had hoped to get all of them accustomed to the pace of practice and how to properly perform every drill.
It cost the team dearly.
"Well, I think you've got to be smart," coach Gus Bradley said. "You weigh it to, 'Hey, we can get them acclimated, a feel for everything.' But we didn't have a regular practice as far as reps. Where we normally go 15 reps, we had 10. We didn't have a blitz period. It's just getting them more accustomed to the flow of practice, as well as being able to evaluate some of these guys that are in for the next two days."
Fowler had 14 1/2 sacks in three years at Florida, including 8 1/2 last season, and was the best player on a solid defense.
The Jaguars wanted the 6-foot-3, 265-pounder to lose about 10 pounds and become a better fit for the team's hybrid end/linebacker position called "Leo."