The Patriots have officially kicked off their offensive coordinator search.

As of Wednesday, there were four known candidates, and likely more to come.

Bill O’Brien, Nick Caley, Adrian Klemm, and Keenan McCardle are all said to be in the mix.

Caley, who has served as an offensive assistant since 2015, most recently as the tight ends coach, reportedly interviewed with the team Wednesday.

Retired Patriots offensive line coach Dante Scarnecchia knows three of the candidates pretty well, and had some interesting things to say about each one.

First up, O’Brien.

From 2007-2011, O’Brien worked as an offensive assistant, wide receivers coach and quarterbacks coach before eventually getting the offensive coordinator title. So he worked right alongside Scarnecchia.

“Billy’s really a well-qualified guy, no doubt,” Scarnecchia said of O’Brien when reached Wednesday. “He’s a good football coach. He’s got family here, he still has a house here out in Harwich. By all accounts, it’s a natural fit.”

Scarnecchia also said O’Brien, who has been Alabama’s offensive coordinator the past two years, would have to weigh if it’s the “right move” for him, given his desire to return to the NFL as a head coach.

Asked about O’Brien’s famous temper, Scarnecchia laughed.

“I think the players used to call him ‘Teapot,’ because that teapot every once in a while got a little hot,” said Scar. “But he was a good guy to be around.”

Klemm?

Scarnecchia coached him for four seasons after the offensive lineman was drafted in 2000. He was Bill Belichick’s first draft pick as head coach of the Patriots, arriving in the second round.

Klemm’s time in New England was punctuated by injury. And while Scarnecchia didn’t sense Klemm was headed for a coaching career, he wasn’t totally surprised how it ended up.

“Where Adrian is concerned, I think his dad was a basketball coach. So coaching was in the blood,” Scarnecchia said. “And certainly, football was important to him. He just had so many injuries when he was with us. That was a tough part of it. But he quickly learned coaching, he found his niche, and by all accounts, he’s done a nice job.”

As for Caley, Scarnecchia is also a huge fan of the Patriots tight ends coach, who also interviewed for the Jets offensive coordinator job on Tuesday.

“Nick’s a bright guy, and a really good football coach. He works very, very hard at it. He speaks very well. He doesn’t mince words. He lets you know how he feels,” said Scarnecchia, who worked alongside Caley for five seasons.

“I always appreciated him for those qualities, and I always enjoyed being around him. I wish him nothing but the best of luck and best of success. I’m glad he’s had the opportunities to interview. I suspect he’ll do very well in the interview process. Cuz he knows football, he loves football, and he’s passionate about it.

“You just have to see how it all plays out for him, but I’m glad he’s getting these opportunities, I really am.”