James Harrison: Belichick more disciplined than Tomlin

James Harrison's storied time with the Steelers didn't get a fairytale ending, as the recently retired pass-rusher forced his way out of Pittsburgh over playing-time issues before joining the rival New England Patriots.

Having played under two of the most successful active head coaches in the league in Bill Belichick and Mike Tomlin, Harrison is uniquely positioned to evaluate their skill sets - or in Tomlin's case, point out his flaws.

"Mike Tomlin is good as a head coach," Harrison said during an appearance on FOX Sports 1's "Undisputed" on Thursday. "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."

Tomlin claimed one Super Bowl and had another title-game appearance during his first four seasons in charge of Pittsburgh, but despite arguably being one of the most talented teams in the league since 2014, the Steelers have yet to come close to adding to their championship collection.

With Ben Roethlisberger turning 37 next year and Le'Veon Bell's future uncertain due to a contract standoff, time may be running out for this iteration of the Steelers to fulfill their potential - and if Harrison is to be believed, the key could be a change in philosophy from their head coach.