NORMAN — Jacob Lacey knew something was wrong when he began to cough up blood.

That was the final straw for the OU defensive lineman, who had been experiencing pain in his leg and shortness of breath the past few days. But it wasn't until Lacey boarded a flight in the spring to watch a friend graduate from Notre Dame that he realized he needed medical attention.

Lacey went to a nearby hospital the following morning at 2 a.m. He found out he had pulmonary embolisms, which is a sudden blockage in the blood vessels that send blood to your lungs.

It had spread from his leg due in part to the lowered air pressure and lack of movement during the flight.

"Doc said I shouldn't be alive," Lacey said. "He looked at me straight up and said, 'I don't know how you're breathing.'"

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Lacey was also told he might never play football again.

Fortunately, the redshirt senior has since recovered from the close call and is back to making plays for OU. And he also has a new outlook on the game of football.

"It changes everything," Lacey said. "I think college football players sometimes might take for granted what they get, with all the glitz and the glam and things like that. But just having the game almost taken away from you in a sense that you can't control ... It really made me appreciate the little things."

Lacey's road to recovery wasn't an easy one.

He had to take blood thinners for the next three months, and he also wasn't able to participate in OU's summer workouts. That was valuable time lost for Lacey, who hoped to get adjusted to his new team after transferring from Notre Dame in November.

But that didn't stop him from preparing for the season. Lacey still worked out at his apartment gym as often as he could to stay in shape.

"It's scary," Venables said. "Fortunately for him and for us from a football standpoint, it was the best-case scenario when it comes to blood clots. I think the minimum amount of time, he was one of those percentages that fit into that category.

"He was very aggressive in wanting to come back sooner rather than later. ... To his credit, he stayed active in all the right ways on his own and did what he could."

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Lacey was cleared to play on Aug. 29, just a few days before OU's season opener against Arkansas State.

He held a modest role through the Sooners' first five games, recording six tackles (one for loss) during that time. But Lacey was named one of OU's team captains for its 34-30 win over Texas on Oct. 7, and he delivered in a crucial moment.

The two rivals were tied at 27-27 with 2:35 seconds left in the game, and Texas had a fresh set of downs at OU's 35-yard line. Quarterback Quinn Ewers gathered the snap and was quickly tackled by Lacey for the Sooners' sixth sack of the contest.

"When the center went away, I saw an opportunity to spike the gap just like we practiced over and over again," Lacey said. "Quinn was sitting right there, and I knew I could make the play. To me, at the time, it felt routine."

The highlight play took momentum away from the Longhorns, who ultimately settled for a 47-yard field goal.

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OU then marched down the field on the following drive, and Nic Anderson hauled in a 3-yard touchdown pass with 15 seconds left to win the game.

"Obviously, it was a big play within there," Venables said of Lacey's sack. "Jacob, one of the things that makes him a really good player is he plays with great fundamentals. ... But good for him. Really big moment for him."

Lacey hopes to have more big moments this season for OU, which is set to host UCF at 11 a.m. Saturday.

But most importantly, he plans to relish every opportunity he gets after his medical scare.

"It made me take a moment a little bit more in each game to really appreciate where I'm at," Lacey said. "But it also allowed me to know I can go as hard as I possibly can each play because at the end of the day, that really could be your last play."

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This article originally appeared on Oklahoman: OU football DL Jacob Lacey bounced back from offseason health scare