It's easy to remember Denny Green's paranoia and malapropisms. The man wore his flaws the way Rollie Fingers wore a mustache. He also won 117 NFL games and advanced to two NFC title games.

Green lasted as a coach not because of interpersonal skills or innovations. He lasted because of one great strength: an eye for talent.

Green could watch a flawed young receiver like Cris Carter and predict greatness, and he could spot a problematic college receiver like Randy Moss and see a star. Early in his tenure with the Vikings, Green often demonstrated his knack for judging talent when choosing assistant coaches.

Leslie Frazier, unlike Green, succeeded as an NFL coordinator before becoming the Vikings head coach. Frazier, unlike Green, is well liked by most of the people who work at Winter Park. Frazier, unlike Green, has yet to demonstrate a knack for finding coaching talent, one of the most important responsibilities of an NFL head coach.

After Roger Headrick hired him away from Stanford, Green assembled a staff that included Tony Dungy, Tom Moore, Monte Kiffin, John Teerlinck, Ty Willingham, Willie Shaw and Brian Billick. Green even brought in two players, Mike Tice and Jack Del Rio, who would become NFL head coaches.

At the time, nobody knew just how impressive that list of names would become.

Dungy rehabilitated a sagging career as Green's defensive coordinator and became an outstanding head coach.

Tom Moore coached receivers for Green. Not until he mentored Peyton Manning as the Colts offensive coordinator would his methods gain fame.

Monte Kiffin coached inside linebackers. He would become one of the great defensive coordinators in NFL history.

Brian Billick coached tight ends. He would win a Super Bowl while running the Ravens.

Willie Shaw coached the secondary for Green; he would become an NFL defensive coordinator. His son now coaches Stanford.

Ty Willingham would become the coach at Notre Dame and Teerlinck would coach the Colts defensive line for Dungy when they won the Super Bowl.

In 2001, when Green lost his job, his coaching staff had lapsed to the point where owner Red McCombs' top choice as Green's replacement was Tice, then an offensive line coach who had never been a coordinator or head coach at any level.

Assistant coaches are vital in the NFL. Head coaches make the most important decisions; coordinators do the most important work.

Frazier has been on the job for more than a year now. His first coaching staff performed poorly.

A charitable view of offensive coordinator Bill Musgrave would hold that he was hamstrung by erratic quarterbacks and limited receivers, and that his strength is developing young quarterbacks, making him a good fit for a franchise relying on Christian Ponder. But Musgrave is in his third stint as an NFL coordinator, and the first two did not end well.

Frazier's pick to be his first defensive coordinator, Fred Pagac, either failed outright or wasn't a good fit to run Frazier's preferred defense. Either way, Frazier made a mistake hiring him, and now Pagac is officially on the job even while Frazier seeks his replacement.

Frazier has fired defensive line coach Karl Dunbar, whose unit was the team's strength last season.

Coming off a 3-13 season and remaining supportive of Musgrave, Frazier has one chance to dramatically upgrade his staff, and that's by hiring a dynamic defensive coordinator.

With Mel Tucker and Raheem Morris taking other jobs, conventional wisdom holds that there are three other top candidates: former Rams coach Steve Spagnuolo, Vikings linebackers coach Mike Singletary and Eagles defensive coordinator Juan Castillo, who could be replaced in Philadelphia by Spagnuolo.

Spagnuolo is an excellent defensive coordinator. Castillo struggled last season in his transition from offensive line coach to defensive coordinator, but the Philadelphia defense improved as the year progressed. Singletary has not proved himself in any way as an NFL coach.

If Frazier can land Spagnuolo, there may be hope for his tenure. If Frazier settles for Singletary, he may be out of a job by next October.

Take it from Denny Green, Leslie: NFL head coaches are often defined by the company they keep in meeting rooms.

Jim Souhan can be heard Sundays from 10 a.m. to noon and weekdays at 2 p.m. on 1500ESPN. His Twitter name is SouhanStrib. • jsouhan@startribune.com