Criminal Minds: Evolution showrunner Erica Messer explains the season 2 comment about Spencer Reid (Matthew Gray Gubler) and his sabbatical. New episodes have followed David Rossi (Joe Mantegna), Penelope Garcia (Kirsten Vangsness) and other members of the Behavioral Analysis Unit amid increasing criminal activity, but Gublers character remains noticeably absent. Reid, whose brainpower and unique personality made him a fan favorite, appeared in 15 seasons of the original series as a fellow Supervisory Special Agent. However, in Criminal Minds: Evolution season 2, episode 7, Emily Prentiss (Paget Brewster) revealed that he’s temporarily away from the FBI.
https://screenrant.com/criminal-minds-evolution-season-2-reid-absence-explained/