Allen told MMQB.si.com he has a dead spot — no bigger than a dime — on his cerebellum. The cerebellum controls motor movement and co-ordination.
The Jaguars released Allen last week after his personal physician consulted with Jacksonville's medical staff before a scheduled physical.
The Jaguars declined comment Tuesday, citing medical privacy laws. Allen, who lives with his wife and two--year-old son in San Diego, did not immediately return a message left on his cellphone.
"I told my story so athletes understand you can't ignore head injuries," Allen posted on his Twitter page Tuesday. "If you're not sure you have one, then you do. Report it immediately."
In the months after Allen's initial stroke diagnosis, he saw three neurosurgeons. The last one advised Allen to quit playing football.
Allen told MMQB he has struggled to pick up and grip hand-held objects — doctors believe this will subside in time — and will be on blood-thinning medication for the rest of his life.
Allen hopes others will learn from his experience.
"Guys talk about it all the time: 'I'm all right; I just got my bell rung,'" he said. "I've had, maybe 10 times in my career, when for a second I felt woozy after a hit. And what I've learned from this is that it's not something to be overlooked. If it feels like something's wrong, something's wrong. I want someone to know my experience, so they can know when they experience something similar."
Allen sustained the concussion and stroke in Week 15 against Buffalo after running into Bills centre Eric Wood several yards downfield.
"It was strange because it was so routine," Allen said. "We hit, I got off the block, no big deal.
"I felt something flash — like they say when you get your bell rung. I didn't lose consciousness. I walked back to the huddle and finished the drive."
Later in the game, though, Allen began having double vision on the sideline. He did not notify team trainers, instead asking teammate Paul Posluszny if his eye was OK.
Allen had a headache after the game and again when he woke up the next day, which prompted him to tell the team.
The Jaguars ordered an MRI and sent Allen home. That Tuesday, the Jags told Allen to meet a team physician at the emergency room. Allen was told he had suffered a stroke and had tests for three days at the hospital.