HAVE patience, San Francisco 49ers fans?

One of the franchise’s most storied offensive linemen turned NFL analyst thinks you’ll need it — and then some.

Randy Cross believes the rebuild time needed for 49ers owner Jed York to field a winner once again will stretch into the next decade as the franchise continues to reel from the departure of head coach Jim Harbaugh following the 2014 season.

“The drain out of the building is something — from a talent standpoint, mentality standpoint, football knowledge standpoint — that’s gonna take them, best-case scenario, at least five or six years to replace,” Cross told SiriusXM NFL Radio.

“Line of scrimmage, quarterback, head coach, everything about it.

“I wish (York) the best of luck. I think the league’s a lot better when the California and Bay Area teams are relevant. But I look at that place right now as being in pretty dire straits when it comes to what’s going to happen.”

Jarryd Hayne of the San Francisco 49ers looks on from the sidelines at Levi's Stadium. Source: Getty Images

Cross points directly at the inability of York and general manager Trent Baalke to coexist with Harbaugh, who was allowed to leave for the University of Michigan after their working relationship became untenable.

Following eight straight seasons without a playoff appearance (2003 to 2010), Harbaugh had taken San Francisco to two NFC Championship games and an appearance in Super Bowl 47 before dipping to 8-8 in 2014 as the behind-the-scenes drama became an on-field detriment.

Even so, that .500 record was worth popping champagne corks for compared to how the club fared under his replacement.

Jim Tomsula was such a disaster that he was fired after the 2015 49ers posted a 5-11 mark.

In his defence, not everything was Tomsula’s fault; the roster was decimated last off-season by retirements and free-agent losses in the wake of Harbaugh’s departure.

San Francisco 49ers chief executive Jed York gestures while speaking to reporters. Source: AP

Said Cross, who won three Super Bowl rings during his time with the 49ers (1976-1988): “I’m gonna be honest with you — I’m not sure if they can recover from that decision to get rid of Harbaugh, which brought on the wave of talent going away, some guys just walking away, others choosing to go somewhere else in free agency.”

Chip Kelly, who was fired in Philadelphia before the 2015 season even ended, is San Francisco’s new head coach.

Critics have ample fodder to question whether the concepts Kelly brought from college football can translate to sustained NFL success.

Cross, though, thinks San Francisco’s problems run much deeper than Xs and Os.

He points to the national embarrassment the 49ers experienced the week of Super Bowl 50 before the game was played at their home stadium in Santa Clara.

Chip Kelly speaks to the media after he was announced as the new coach of the San Francisco 49ers. Source: AFP

The franchise was skewered for cancelling a mass Girl Scout sleepover scheduled for May in favour of a concert that would have generated more revenue for the franchise.

The public outcry from the money-grab caused the 49ers to reverse course and reschedule the Girl Scouts event (and pick up the tab for it, too).

“For right now, (the 49ers) just gotta learn how to get out of their own damn way,” Cross said. “A great example is that thing with the Girl Scouts. During the Super Bowl week — really? “That does not scream to me that we know what we’re doing.”

Unlike when Cross was playing for the 49ers and York’s uncle Eddie DeBartolo Jr. — who was recently elected into the Pro Football Hall of Fame — ran the show as team owner.

This article originally appeared on Fox Sports’ US site