It's safe to say Reid is still making his way through the five stages of grief on Criminal Minds.

On Wednesday's episode (9/8c, CBS), Reid (Matthew Gray Gubler) is firmly in the denial stage in the wake of Gideon's death, as he retreats to back of the BAU jet to play his and his late mentor's favorite pastime chess... by himself.

Postmortem: Criminal Minds boss on that big death and why it had to happen

"Playing yourself is difficult," he tells Rossi (Joe Mantegna) in the exclusive sneak peek above.

"Playing a ghost even more so," Rossi replies. "He's gone, Spencer. Keeping the game going won't change that."

So how does Rossi help him move on? Check out the clip to find out.

Criminal Minds airs Wednesdays at 9/8c on CBS.

(Full disclosure: is owned by CBS.)