Retired New York Giants halfback Brandon Jacobs called San Francisco 49ers coach Jim Harbaugh a "b----" on Thursday during a radio interview.  Jacobs said his only regret was signing with the 49ers in 2012, CBS Sports reports.

Jacobs signed with San Francisco in 2012 but played in only two games because of injury.  He criticized the 49ers on social media, which led to the team suspending him and eventually releasing him. 

After retiring earlier in January, Jacobs took to WFAN's "Boomer and Carton" show on Thursday and shared his feelings about Harbaugh.

"He is a b----, and that's why he's never won anything," Jacobs said, via CBS Sports.

Jacobs also touched on his brief stint in the Bay Area.

"I have one regret in my career, and that's going to the 49ers when I could have stayed in New York," he said.  "I just wanted to see what stuff was like with another team and it didn't work out."

Jacobs said he "wasn't liked" and felt like the 49ers were holding him hostage.

"It is what it is," he added.  "I've got two rings.  Harbaugh, though, he's a b----.  So it doesn't matter."

Jacobs, 31, announced his retirement on Jan. 2.

"After 9 years in this whirlwind business they call the NFL, I am proud to announce that I am hanging up my cleats," Jacobs tweeted.  "I've had an amazing run and I appreciate all of the support from the fans through the good and the bad.  The New York Giants are a great organization and I am proud to have been a part of it for so long. 

"I love my coaches and my teammates and will miss them as well as the game itself but I am healing well from my surgery and I look forward to running around with my kids for years to come."

He finished his NFL career with 5,095 rushing yards and 60 touchdowns.