Brandon Jacobs played one year under Jim Harbaugh as a member of the San Francisco 49ers. And that was enough for him.

The running back had just 7 yards on 5 carries in two games in 2012 for a team that went 11-4-1 and beat the Atlanta Falcons in the NFC Championship Game to reach the Super Bowl. Jacobs, however, told CBS Sports Radio's Tiki and Tierney that Harbaugh had little to do with it.

“Let’s be real. They had great assistant coaches, but Jim didn’t know what he was doing. Jim had no idea. Jim is throwing slants into Cover-2 safeties, getting people hurt. That guy knew nothing, man.”

You can listen to his rant here:

Jacobs played nine NFL seasons, mostly with the New York Giants where he won two Super Bowls. He played on season at Auburn before transferring.

Harbaugh, in his second year as Michigan’s head football coach, had his own response on Twitter: “Biblical advice for [Jacobs]. Let all bitterness & wrath & anger & clamor & slander be put away from you, along with all malice.”

But it didn’t end there. Jacobs responded to Harbaugh, challenging him: “Draw up cover 6 and post it.”

He followed up with another play request and one another jab: “Don’t ask any of your assistant coaches either.”

And lastly a post that was later deleted:

Love the support but stop the super bowl talk. I will expose him, Michigan will fire him when I am done.

— Brandon Jacobs (@gatorboyrb) May 27, 2017