Williams told WBTV in an exclusive interview Monday that he was cut by the Panthers last week during a meeting with coach Ron Rivera and general manager Dave Gettleman.
"We sat down, and he told me, 'The fact of the matter is we're going to have to release you,' " Williams told the station. "I said, you know, 'Why?' and he said, 'Because we don't run the ball enough. Just like you said back before the season started, we don't run the ball enough to keep you and [Jonathan Stewart] both, so we're going to release you.' "
Carolina will save $2 million in salary-cap space by designating Williams as a post-June 1 cut. Williams has one year left on his deal and is scheduled to count $6.3 million against the 2015 salary cap. According to the collective bargaining agreement, the Panthers have to wait until the new league year begins March 10 to designate Williams as a post-June 1 cut, two league sources said.
Gettleman wouldn't go into details at the combine about his talk with Williams last week.
"I spoke to DeAngelo. We had a great conversation. It's confidential. It's between us," Gettleman said. "DeAngelo had a tough season. He lost his mom, who he was very close to. Then came the season and he just couldn't stay healthy. It was really hard for him.
"Then he broke his hand against Minnesota. That's hard. Especially when you're 32 [in April]. But he finished the season like a pro's pro and like a man's man. I really respect DeAngelo for the way he finished it."
Asked directly if Williams would be a part of the team in 2015, Gettleman said, "I'm going to leave it where I just left it."
Williams told WBTV that one reason he is all right with the release is the Panthers, including owner Jerry Richardson, didn't reach out to him when his mother died of breast cancer in May.
Williams led the NFL's breast cancer awareness movement when he learned a few years ago that his mother had the disease.
"There was a couple of things that upset me about the Panthers when my mom died," Williams told WBTV. "Nobody came to the funeral. The owner didn't reach out. He didn't say anything."
On Twitter, Williams later said in a debate about whether the Panthers reached out, "I was referring to the owner and leadership, not rivera and teammates.''
A team representative said Williams has not officially been released and that no transaction is expected Monday.
Williams had been going to rehab at Bank of America Stadium, a league source said. A team cannot release a player who is injured without an injury settlement.
Williams told WBTV the entire conversation lasted around 10 minutes and was the last he has heard from the team.
"[Stewart] had the hot hand at the end of the season," Williams said. "He's a great running back, obviously. I don't feel bitter at all. It's a business. And that business comes back and reminds us year after year -- whether it be Steve Smith, whether it be Jordan Gross, whether it be myself -- it's going to happen to every guy in that locker room, so it doesn't bother me at all."
The Panthers released Smith, their all-time leading receiver, in the offseason last year.
Williams has been with Carolina since it made him the 27th pick of the 2006 draft. He has 6,846 career rushing yards and 46 rushing touchdowns.
Injuries limited him to six games in 2014. A broken hand late in the season allowed Stewart to step up and take the bulk of the carries. Stewart was one of the leading rushers in the league over his final six starts, including two playoff games, with 594 yards.
Meanwhile, left tackle Byron Bell announced on Instagram that he would not be with the Panthers in 2015.
Bell was scheduled to become an unrestricted free agent March 10. Rated next to last among tackles graded by Pro Football Focus in 2014, he was not expected to be a factor at left tackle in 2015.
Under the Instagram account of bbell077, he wrote: "It's been real in Carolina now time to see where the Lord takes me next,! Can't be mad 4 years would love more but hey it is what it is I guess just got to keep pushing the Lords work and growing as a Christ!"
The Panthers are expected to pursue a left tackle in free agency or the draft.