TMZ.com’s Claude Brodesser-Akner is reporting that “insiders [are saying] that Warner Bros. was caught by surprise at an unexpected announcement of a Departed sequel in the press by the loose-lipped Mark Wahlberg — the only surviving principal character from the first film. And as a result, the follow-up project’s planning is vastly complicated,” largely because of questions about the participation of Paramount Pictures chief Brad Grey.

Paramount honcho Brad Grey, Warren Beatty at the Paramount party on Golden Globes night

“In fact, insiders say that all deals associated with the project are on hold until the studio can figure out what Grey’s involvement would be,” Brodesser-Akner writes. “After all, before he was chairman of Paramount, he helped create Brad Pitt‘s production company at Warner Bros., which developed the present-tense, Oscar-nominated Departed.

“Grey declined to speak to TMZ about what role he’d have in the new Departed, But now that the news of a planned sequel is out of the bag, things are complicated: For one thing, it’s being made at a rival studio, putting Grey in an odd, conflicted position if he is produces it for Warners. For another, if Grey pushes to be the sequel’s producer, it might signify that he’s thinking of packing a parachute because he suspects he’ll soon be out of a job at Paramount.

“Grey’s future is a matter of open speculation in Hollywood these days: Having just last month fired his studio president, Gail Berman, after a tumultuous run, Grey appears embroiled in a battle for control of the studio with DreamWorks co-founder David Geffen. It was Geffen who last year brought in Universal Pictures chairwoman Stacey Snider to run the now Paramount-owned DreamWorks.

“As the Times‘ Claudia Eller noted on 1.29, “Though Grey signed off on her hiring, the move was widely viewed as an effort by Geffen to position Snider for Grey’s job.”