Fans of Chuck, prepare to be transported to Nerd-vana.

Following the casting of Quantum Leap’s Scott Bakula as Chuck’s dad, sources confirm to me exclusively that another sci-fi icon has been tapped for the show. Robert Patrick, a.k.a. the T-1000, is slated to appear midway through the third season.

But rather than coming from the future, Patrick will play Col. Keller, a mysterious figure from Casey’s past in “Chuck Versus the Tic Tac,” which I hear will be a big episode for Adam Baldwin’s newly-minted colonel.

Sadly for all you Buy More shoppers, there’s still no definitive news on Chuck’s return date. (Additional reporting by Keith Staskiewicz)