According to a report from local station WTOL, Douglas was shot outside Gino's Pizza around 11:30 p.m. after police said a fight broke out between two men.
Police on Wednesday arrested 24-year-old Michael Mitchell on murder charges.
Douglas, a junior, grew up in Toledo and went to Start High School, where he played both offensive and defensive line and was named first-team AP All-Ohio in 2016.
A communication major, Douglas appeared in 12 games in his first two seasons with the Rockets.
Toledo coach Jason Candle tweeted a statement Wednesday morning, calling Douglas a "bright and hard-working young man who was loved by all his teammates and coaches."
Those we love never truly leave us. JD will forever be part of the Rocket Family and his infectious smile will never be forgotten. Our prayers are with him and his family. #RIPJD #OneRocket pic.twitter.com/ROrKcWUyyG— Jason Candle (@CoachCandle) July 8, 2020
Mike O'Brien, Toledo vice president and athletic director, also released a statement Wednesday.
"We were all shocked to learn of the tragic death of Jahneil Douglas," he said. "This is a devastating loss for our football team and our University, and a very sad day for all of us in Rocket Nation. Our deepest condolences go out to Jahneil's family and friends."