Former NFL quarterback Johnny Manziel was reportedly hospitalized on Monday for a "reaction" to prescription medication.

According to TMZ Sports, Manziel was admitted to a hospital in Humble, Texas. He was in the area to attend the JMBLYA concert with friends after playing in a golf tournament hosted by friend and former Texas A&M teammate, and current Tampa Bay Bucs wide receiver, Mike Evans. 

Manziel has since posted a message on Instagram, explaining that he had a reaction due to an increased dosage in Lithium.

"Thank you for your concern and kind messages. Unfortunately I had a reaction to an increased dosage in Lithium which I take for my Bipolar disorder. It was a scary moment and I'm especially grateful for the staff at the hospital and all that they've done in the last 24 hours."

During an interview with Good Morning America that aired back in February, Manziel admitted to being diagnosed with bipolar disorder "about a year ago" and says he has been taking the proper medication. The 25-year old QB recently participated in the developmental Spring League and has a standing offer from the CFL's Hamilton Tiger-Cats.