You either love him or you hate him. There’s really no in-between when it comes to Jim Harbaugh.

Former NFL running back Brandon Jacobs apparently wasn’t one of the people that loved him. He made that pretty clear when he appeared on the Tiki and Tierney show on Thursday.

Jacobs, who was a member of the Harbaugh-coached San Francisco 49ers in 2012, said Harbaugh “didn’t know what he was doing,” and “didn’t know anything,” when it came to coaching in the NFL.

He also said that Harbaugh’s play-calling was “getting people hurt.”

That’s a pretty harsh criticism for a head coach that turned around a floundering Stanford program, led the 49ers to the Super Bowl and has posted back-to-back 10 win seasons at Michigan.

Jacobs, who is primarily remembered for his time with the New York Giants, was in San Francisco for a brief, one-year pit stop. He played in just two games and had seven yards for the year.

In the interview, Jacobs also admitted that he and Harbaugh didn’t see eye-to-eye, which might be why the running back is dishing out a few jabs at his former head coach.