After days of waiting, Robert Kraft and the New England Patriots finally did it.

The owner on Thursday brought an end to Bill Belichick's unparalleled run with the franchise, reaching a "mutual agreement" with the six-time Super Bowl-winning head coach to fracture their partnership. While this season's 4-13 campaign was undeniably a crash landing for an organization that Kraft was eager to see return to the playoffs, the split still marks a stunning end to one of the most prolific stretches in NFL history.

It's only appropriate, then, that this new embrace of the unfamiliar starts with something relatively foreign: a coaching search. Kraft has embarked on just three of them in his 30 years of ownership.

Where Kraft goes from here is anyone's guess, as the owner on Thursday focused on Belichick's departure rather than detailing any thoughts about the future of the franchise. But multiple reports have indicated that Kraft could look to familiar figures as leading options to take over.

Here are five candidates who could be on the Patriots' radar:

Mike Vrabel

His surprising dismissal from the Tennessee Titans surely adds a wrinkle to this coaching search. Kraft has been laudatory of Vrabel dating back to the former linebacker's days with New England, which included helping the franchise win three titles as a linebacker. Given his ties to the past regime while not technically being a part of the Belichick tree, he might offer the chance for New England to thread the needle on moving on from this storied era without totally facing the unknown. After all, he was 54-45 during the regular season in six years with Tennessee. And it's clear that the Patriots would at least have a leg up on other teams potentially pursuing Vrabel, as his comments when being inducted into the Patriots Hall of Fame made clear his reverence for the organization.

"I don't want you to take this organization for granted," Vrabel said. "I've been a lot of places; this is a special place with great leadership, great fans, great direction and great coaching. Enjoy it, it's not like this everywhere."

Jerod Mayo

On a different timeline, Mayo might have been the clear choice as Belichick's successor. The linebackers coach, 37, withdrew from consideration for the Carolina Panthers coaching job last season. Kraft said last offseason that he was certain Mayo would be a head coach in the near future, noting, "I hope he's with us." Had Belichick's post-Brady portion of his time in New England been more successful - and extended another few years - Mayo would have made for a natural successor. Now, it's time for Kraft and Co. to assess whether the team's former standout linebacker is ready for the job of taking over for a coaching legend. Mayo, however, would allow the team to move forward with a link to its history while still embracing a fresh, modernized perspective.

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Brian Flores

There are several former head coaches from the Belichick tree who could at least be on Kraft's radar for this search, including current Patriots offensive coordinator Bill O'Brien and former Las Vegas Raiders head coach Josh McDaniels. Flores, however, might be the best-positioned of the former New England staffers to make a strong case for the job. His coaching credentials are impeccable, as the Minnesota Vikings defensive coordinator vexed opposing quarterbacks throughout this season with his confounding blitzes. Still, his outstanding lawsuit against the NFL could complicate matters, particularly since his inclusion of text messages sent by Belichick was a central part of his case. His handling of Tua Tagovailoa during his time as head coach of the Miami Dolphins might also be a strike against him. He has to be considered substantially less likely for the role than Vrabel and Mayo, but don't rule him out entirely.

Ben Johnson

This would be quite the departure for Kraft, as the Detroit Lions offensive coordinator doesn't have any links to Belichick or the Patriots. But if the owner is intent on revving up an attack that bested only the Aaron Rodgers-less New York Jets in yards per game this season, Johnson would prove plenty sensible. The 37-year-old has been revered by those who work with him for his humble approach, but it's the results, of course, that have helped earn him acclaim and a spot as likely the most-sought after candidate at the coordinator level this cycle. In leading the Lions to consecutive top-five finishes in both yards and points per game, Johnson has established himself as a masterful tactician. What might he be able to accomplish with full reign over a franchise that looks ripe for a reboot?

Jim Harbaugh

Now we're into the outright long shots. Not only does Harbaugh have no link to the Patriots, the Michigan coach would also be an odd fit as successor given his idiosyncrasies and nearly decade out of the NFL. Still, his track record of turning operations into winners is evident, and he's shown he can develop quarterbacks. Even an interview isn't certain, but he likely warrants at least a discussion.

This article originally appeared on USA TODAY: Who will replace Bill Belichick? Mike Vrabel, Jerod Mayo stand out