BALTIMORE (WJZ) — A “high-ranking U.S. military official” cautioned the Ravens against signing Colin Kaepernick in 2017, according to a TMZ report.

With Joe Flacco nursing a back injury last summer, the Ravens were one of the only teams to show interest in signing the controversial quarterback.

Kaepernick led the 49ers to the playoffs in 2013, and ultimately Super Bowl XLVII, where they lost to the Ravens. During the 2016 season, he would often take a knee during the national anthem ahead of games in protest of police brutality.

That drew lots of criticism for the 2011 second round draft pick, and he has been a free agent since opting out of his contract with the 49ers last March.

The TMZ report alleges that coach John Harbaugh sought advice from friends while he was considering Kaepernick.

One of those, the military official, “didn’t outright say, “Don’t sign Kaep” — but advised the team to give Colin a set of specific guidelines he needed to follow if he wanted to keep his job,” per TMZ.

In September, former Raven Ray Lewis told Showtime’s “Inside The NFL” that the reason Kaepernick wasn’t signed was due to a controversial tweet from Kaepernick’s girlfriend, Nessa Diab, which appeared to compare Ravens owner Stephen J. Bisciotti and Lewis to a slave owner and a slave.

“We were talking about giving this kid an opportunity to get back in the National Football League,” Lewis said. “I have been fighting for this kid behind the table like nobody has… Then, his girl goes out and puts out this racist gesture and doesn’t know we are in the back office about to try to get this guy signed.”

Follow @CBSBaltimore on Twitter and like WJZ-TV | CBS Baltimore on Facebook