LeBron James can’t say that he wasn’t warned.

Lots of us were crowing in the summer, and pretty loudly so, about what would greet the unquestioned Lord of the Eastern Conference if he dared to defect.

Sign with the Los Angeles Lakers if you wish, for the sunnier Hollywood life and all the perks, but brace yourself for the most trying regular season of your career if you decide to go West.

That was the gist of the scouting report — which in retrospect could not have been much more prescient.

On cue: The most daunting and, yes, disappointing season of James’s career is right here, right now, for the biggest name in basketball.

And it appears he will soon have to stomach that it’s going on his ledger in the most permanent ink that he was unable to bring a halt to the longest postseason drought in Lakers history — barring an unforeseen resurrection from a fractured group that sits four and a half games out of a Western Conference playoff berth with 19 games to go.

No matter how much culpability you wish to assign James for what is poised to go down as the Lakers’ franchise-record sixth successive trip to the draft lottery, he’s going to have to own this as much as the front-office tandem of Magic Johnson and Rob Pelinka as well as the under-fire coach Luke Walton.

The LeBron Way, for years and years, has worked something like this: He inevitably gets most of the credit when his team flourishes; his teammates absorb the bulk of the blame when things unravel. But this is different. This would be the jarring sight of James, fresh off his eighth consecutive finals appearance, actually missing out on the N.B.A. postseason for the first time since his second professional season in 2004-5, when he was just 20.

Even though he can rightly point to his recent groin strain as the biggest standings-altering disruption these Lakers have endured, James surely understands that his maiden campaign in Los Angeles is bound to be recorded in many precincts as a failure to make the playoffs that belongs to him. The Lakers are 4-7 since James returned from the groin injury that sidelined him longer (17 consecutive games) than any previous injury in his 16-year career. They have followed up an unsightly road loss to Atlanta in their final game before the All-Star break with harder-to-rationalize road losses to New Orleans, Memphis and Phoenix since the break.

After Saturday night’s humiliation against a 13-51 Suns team, which dropped the Lakers to 30-33, James’s gang only sports a 1.3-percent chance of reaching the postseason, according to Basketball-Reference.com.

They also have the league’s eighth-toughest remaining schedule, according to Tankathon.com.

We’ll never know if the Lakers, who had risen to a heady fourth in the West at 20-14 when James sustained the groin injury in a Christmas Day rout of Golden State, could have kept building upon that promising start with a healthy LeBron. But we most certainly do know that James’s mere return to the lineup, at 34, wasn’t enough to rescue a roster that has been assailed since conception for its lack of perimeter shooting and its defensive deficiencies. Nor has he been able to galvanize a locker room that was deeply destabilized by the Lakers’ trade pursuit of the New Orleans superstar Anthony Davis, which became all-consuming in late January, and has never recovered.

It obviously doesn’t help that James, after missing two key free throws in the final minute Saturday, is also converting a substandard 66.9 percent of his attempts from the line to give his critics more handy folder.

Leaving his home-state Cleveland Cavaliers for the Lakers last July without the accompaniment of a second superstar meant that James, in a far deeper conference, would have little margin for error just to reach the playoffs. When you combine James’s injury absence with the continuing post-Davis malaise and the team’s declining ball movement since Lonzo Ball (ankle) was sidelined six weeks ago, it adds up rather quickly to a margin that is long gone.

The calls for Walton’s dismissal, as they were in January, remain nonsensical. A coaching change now, much like New Orleans’s decision to fire General Manager Dell Demps shortly after the trade deadline, would have no discernible effect on the Lakers’ short-term prospects beyond providing their frustrated fans with a “See? We did something” sacrifice.

The prevailing assumption in league coaching circles remains that Walton will almost certainly be dismissed after the season, followed by the Lakers resuming their trade quest for Davis. But denying Walton an opportunity to at finish out a season wrought with drama and distraction since James’s first dribble in purple and gold would be cruel and needless.

Changes are coming, though. It’s an open secret that a big off-season reset looms in Lakerland. James always knew that his new club would not be in the title mix until his second campaign as a Laker, but his patience predictably faded quickly — one more reason desperation has become so palpable around this team.

Many of us know-it-alls in the news media indeed wrote in our preseason forecasts that the playoffs were no certainty for these Lakers, as constructed, but very few of us were actually willing to outright predict that they would miss out. Reason being: It’s not very smart to bet against LeBron Raymone James.

Yet we’ve suddenly reached that unprecedented juncture where it would be wholly irresponsible to advise you that James can extricate himself from this jam just because he’s LeBron. Whether it’s the lingering effects from his groin injury, or his own unmistakably waning spirit in the face of increasingly bleak odds, James has been lacking the zip you associate with his well-chronicled playoff mode — which he assured us on Feb. 21 had been “activated” earlier than usual.

I briefly stood beside James on the floor in Charlotte, N.C., before the All-Star Game tipped off and bought into the idea a surge was coming when he insisted he was eager to embrace “the challenge” of hauling the Lakers out of their hole.

“And I’m getting healthy, too,” James said that night.

A mere two weeks later, it’s already time to start imagining the N.B.A.’s first spring without King James after watching him for eight straight Junes — and wondering how on Earth he’s going to cope with not being a part of it.