The “Boy Genius” Dr. Spencer Reid, played by Matthew Gray Gubler, is one of the most popular characters on “Criminal Minds.” As a result, fans were understandably disheartened when this socially awkward member of the Behavioral Analysis Unit was sporadically absent from the show, starting in Season 11.
"Criminal Minds" executive producer Erica Messer explains that Matthew Gray Gubler’s contract included time off to work on other projects. Given his 11 years playing the same character, taking some time off is only understandable, although the sporadic absences raised a lot of eyebrows in the fan community.
Dr. Spencer Reid’s absences were explained on the show by either having him away visiting his mother, or by sending him to teach seminars to other agents (as was mandated to him by the FBI). However, even with his unofficial "part-time" status in later seasons, Gubler still had plenty of significant storylines.