Five years. Each one better than the last. Golden State Warriors, of course, at the top of the heap, were on his radar.

Brad Stevens' career as an NBA coach was on a trajectory to Gregg Popovich status, sans the multiple championships.

The ball is always moving. Team defense is as important as scoring. Out-of-bounds-play extraordinaire. Coaching up average talent. Entertaining brand of ball to watch.

Then 2018-19 happened.

The ball didn't move. There were not a lot of smiles. Gordon Hayward's ankle or head, or both, were a mess. Players, particularly the young, unproven ones, complained. Kyrie Irving called LeBron James (LOL), apologizing for being such a young, know-it-all heel in Cleveland.

And Stevens' ability to coach NBA players was called into question.

Crazy. A year later and Stevens "Hall of Fame" nomination is put on ice.

Let's be honest, Celtics president Danny Ainge didn't do Stevens any favors.

The Celtics biggest problem this past season -- having too many worthy players and not enough minutes -- was really a problem last June.

Too many players had something to prove this year and not enough minutes to prove it.

Stevens was never able to successfully manage those unhappy players and their egos, which is a big part of being an NBA coach, especially in May and June.

Much to our surprise, Stevens had problems winning over Kyrie, who seemed to go it alone too much, the anti-thesis of Stevens' plan.

Is Kyrie a coach killer? Maybe. He's not easy to deal with. He didn't appear to understand what being a leader entailed.

But "The Next Popovich" is supposed to be able to win Kyrie over and buy-in, right?

Stevens is blamed for the Hayward mess this season, playing him "more than he deserved" at the expense of others. But didn't he have to see if Hayward could break out of the funk he was in for most of the year, possibly making the Celtics a legit championship contender?

There was another big critic of Stevens' job performance this past season: Stevens himself.

"I'll be first to say, as far as any other year I've been a head coach, this was the most trying season," he said in Milwaukee after the Game 5 loss. "I did a bad job. At the end of day, as a coach, the team doesn't find its best fit, as a coach, that's on you."

Stevens is embarrassed about the last nine months. Behind the nerdy look is a competitor.

You don't take a mid-major collegiate team -- Butler -- to consecutive NCAA tourney championship games with talent alone.

I don't know if it's in his nature, but he needs to take control of the Celtics ... again.

Tatum and Brown, who both seem to be nice, young men, should not be allowed to sulk. Their time is now. No excuses. They also need to know last year will not happen again, at least from Stevens' perspective.

It appears Stevens is the big winner in the Kemba Walker for Kyrie trade. Walker is low maintenance and smiles a lot. He appears to be a team-first guy despite his big paycheck.

The point is Stevens is a successful veteran NBA coach with high aspirations. He needs to act that way.

This Celtics team is not expected to compete for a championship. But guess what? We had a lot of fun around here watching a few of those Stevens'-led teams.

You can follow Bill Burt on Twitter at @burttalkssports or email him at bburt@eagletribune.com.