Then, at 5:05 p.m. California time on July 1, it happened: LeBron James announced via his agent Rich Paul’s Twitter feed that he had decided to leave his home-state Cleveland Cavaliers — for the second time — to sign the four-year contract Buss and Johnson offered him.

Just like that, the Lakers became the Lakers again.

Or so they hope.

As I explain in this On Pro Basketball column, James’s debut campaign with the Lakers is perhaps the most difficult regular season he has faced since his second season in the N.B.A. with the Cavaliers, way back in 2004-05.

That was arguably the last time one of James’s teams, in the eyes of preseason prognosticators, was seen as a better bet to miss the playoffs entirely rather than to win the N.B.A. championship.

On a momentous Monday across the league, with teams staging a flurry of news conferences in advance of N.B.A. training camps starting Tuesday, James made his first public appearance in a Lakers uniform. He took nearly 15 minutes of questions about the challenges ahead with his new team, looking and sounding rather serious.

James’s demeanor would suggest he already recognizes how much work and meshing it will take for this group — without a clearly established second superstar — to get anywhere near the Western Conference elite as currently constituted.