"I'd lost a bunch of weight. I lost a bunch of strength," Jensen said. "I wasn't playing well. I was getting beat a lot."
He added that around the same time that he was cut from the Ravens' roster, his father mentioned that he had noticed a change in his behavior.
"We went out to dinner. My dad called me a couple of days later and goes, 'You're not acting like yourself, your mom broke down crying. You weren't being my son, you were being mean,'" Jensen said, adding that to hear from his father that he was being mean to his mother "broke me down."
Jensen said that he didn't know what was happening to him, but his father suggested that he get tested for sleep apnea, a disorder in which a person frequently stops breathing during sleep.
"I'd go to bed at 9, 9:30, you know, be asleep by 10," Jensen said of his sleep schedule.
He adds that despite being in bed for eight, nine, or ten hours, "I'd wake and I'd feel like I got hit in the face with a sledgehammer."
"I'd be in bed for that long. But I just didn't feel rested ever," Jensen said.
Jensen said that his wife used to wake him up in the middle of the night and tell him that he was not breathing.
"She would, you know, smack me, like, 'Hey, wake up. You're not breathing,'" Jensen said. "Then I'd get mad at her because she woke me up. But really, she was doing it because she was ... scared for me, because I would stop breathing for an extended period of time."
Jensen eventually used an at-home sleep test, attaching sensors to different parts of his body and measuring his oxygen levels throughout the night. Doctors told him that the results of the test indicated that he was only getting about 90 total minutes of sleep per night.
"I believe he was waking up 15 times an hour and imagine that happening every hour of your sleep, every night," Cynthia Soriano, a physician with the Central Maryland Sleep Center told ABC News.
"Athletes are larger and heavier, they have a thicker neck area and there's collapse of upper airway when you're sleeping, these tissues are lax," Soriano said. "They can obstruct your airway."
Following Jensen's diagnosis, he started to use a CPAP machine, which forces air into his mouth and keeps his airways open as he sleeps, to treat his sleep apnea.
Jensen told ABC News that a few nights of using the machine, "changed everything," and after one month of using it, his weight went up, his strength was back, and he even returned to the team.
This season, he's poised to be the Raven's starting center.