The retired running back took vulgar shots at 49ers' coach Jim Harbaugh in an interview with New York radio station WFAN Thursday morning. Jacobs repeatedly called Harbaugh an obscene name.
"He is a bitch, and that's why he's never won anything," Jacobs said.
Jacobs signed with the 49ers in 2012, but he played in just two games due to injury. The team also suspended him for conduct detrimental to the team before releasing him.
Jacobs returned to the New York Giants this season, rushing for 238 yards and four touchdowns in seven games. After the season, he announced his retirement.