Russell Allen stroke leads to retirement: "We serve a God who is bigger than our struggles," says 27-year old NFL linebacker

The "failed physical" that the Jacksonville Jaguars announced caused Russell Allen to be dropped was actually a career-ending, on-field stroke.

Allen, a devout Christian football player, was injured after colliding head-on with Buffalo Bills center Eric Wood on December 15.

Doctors advised the former linebacker never to play football again after the hit caused a lasting headache, double vision, and brain damage.

In an April 22 interview, Allen said that it was a good hit, similar to ones that he had taken countless times before.

"It was strange because it was so routine," Allen told MMQB. "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."

Allen didn't consider that he may be injured until he had double vision on the sideline.

"I remember him telling me to look in his eyes," his former teammate, Paul Posluszny said. "He kept asking, 'Is my eye OK?' I looked at him and said, 'Yeah, it looks fine.' I couldn't tell the seriousness of the situation. How do you tell?"

Allen himself couldn't tell, and he played the rest of the game without notifying anyone else that something was amiss.

After a headache lasted through the night and into the next day, however, he became concerned. Allen contacted the Jaguars, and they sent him to the hospital for an MRI.

The test showed that that hit was hard enough to interrupt the blood flow to his brain. The 27-year old had suffered a stroke.

Now, Allen wants to encourage NFL players to speak up if they don't feel right after a play.

"If it feels like something's wrong, something's wrong," he told MMQB. "I want someone to know my experience, so they can know when they experience something similar."

The San Diego native stated that he gained perspective after his injury, and after fellowshipping with his neighbors, Pastor Robert and Stefanie Herber of the All Peoples Church.

"God changed our life through those people," Allen said. "It started to sink in for me what it was all about. You play the game because you love it, and you want to honor it. You treat people with respect and do things the right way, and you keep it in perspective, keeping family and faith up front.

"Those were lessons I learned down the road. I didn't always have that perspective. I learned my lesson."

Earlier today, Allen, also sent a tweet to his followers:

Allen and his wife Ali have two children together; 2-year-old son Parker and a newborn baby girl.