PITTSBURGH -- James Harrison prefers Bill Belichick's disciplinary coaching style over Mike Tomlin's.

Harrison, the Pittsburgh Steelers' all-time sack leader who played much of his career for Tomlin before joining the New England Patriots for the end of this past season, said on Fox Sports 1's "Undisputed" that Belichick is the better coach.

Asked if Belichick is better "by far," Harrison said yes.

"Mike Tomlin is good as a head coach," Harrison said. "He's a players' coach. I think he needs to be a little bit more disciplined.

"The big thing with Belichick is he's very regimented, he's disciplined, everyone is going to be on the same page, there's not going to be anything as far as someone doing their own thing. I think over there [in New England] their whole coaching staff is like that."

Harrison did not leave Pittsburgh on ideal terms. He was released by the Steelers in late December, in part because he forced his way out by leaving games early and sleeping through or missing meetings as an informal boycott for not playing in the rotation.

The Patriots then signed him.

Tomlin was involved in the decision to release Harrison, who was led to believe he would play more when he signed a two-year contract in March 2017. Harrison played 14 of his first 15 seasons in Pittsburgh but finished his career with Belichick in New England, playing linebacker for the AFC champions.

Belichick's structure and intense meeting schedule helped Harrison pick up the defense quickly and even had Tom Brady running down hallways so the quarterback wouldn't be late, Harrison said.

Asked what Tomlin can do to upgrade his player discipline, Harrison said, "just being more consistent across the board with everything. From your stars to your special-teams players."

He added that it's easier for a coach to hold everyone accountable so "it don't look like you're playing favorites."

Harrison announced his retirement this offseason.