LeBron James reportedly informed the Cleveland Cavaliers, his current employer, on Friday that he was exercising his option to become a free agent rather than remaining under his current contract for another year.

The decision vigorously revived an annual phenomenon in the N.B.A. that is unknown to every other sports league: One person grabs hold of the collective psyche of fans, team officials and even civic leaders, single-handedly in control of their fortunes.

If James decides to join your team, you are instantly an N.B.A. title contender, and your city feels the lift. If James decides to leave your team, you are the Jackson 5 after Michael left the band, or “The West Wing” after Aaron Sorkin’s departure — looked up to fondly with nostalgia but otherwise obsolete.

James, 33, has successfully turned the high-stakes drama of free agency into his own reality show. He is the N.B.A.’s best player and its most captivating presence. He is also one of its savviest power brokers, and he has developed a summer ritual of holding the rest of the N.B.A. and entire metropolitan areas in a state of expectancy as he weighs his options every July.