David “Doc” O’Connor was one of the young turks at CAA who helped shape the agency into the modern Hollywood superpower that it is after the exits of co-founders including Ron Meyer and Michael Ovitz. The question was always how long that core group of partners — including Bryan Lourd, Richard Lovett, Kevin Huvane (and the late Jay Moloney) — would stay there. Now comes word that O’Connor is going, with the native New Yorker taking a gig as CEO of Madison Square Garden.

Deadline has confirmed the news, and is hearing that no departure date has been set. The new job is well suited for O’Connor: a longtime NY sports fan, he was one of the key figures in the formation of CAA Sports. He has long been part of the agency braintrust and has been one of the highest-paid agents in Hollywood for years.

O’Connor still has a sizable stable at CAA, with heavyweight clients like Jerry Bruckheimer, Bruce Willis, David Koepp, Eric Roth, John Lee Hancock and director Gary Ross.