Criminal Minds” has undergone a number of changes over the years. But Season 12 also saw its fair share of cast shake-ups with some members exiting, others getting promoted and a new character joining the CBS series’ BAU (Behavioral Analysis Unit).

Shemar Moore, who played FBI Agent Derek Morgan on the long-running crime procedural, exited “Criminal Minds” in Season 11. Season 12 will show the FBI replacing the dark and handsome agent with Fugitive Task Force leader Luke Alvez (Adam Rodriguez).

In the Season 12 premiere, tough-as-nails Alvez would have successfully caught eight of the escaped 13 serial killers. By the end of episode 1, Alvez will join the BAU full-time to help track the remaining five, including the infamous murderer that uses mind-controlling drugs, Mr. Scratch. Although he’s a stellar agent, how will the team feel about Morgan’s replacement? Specifically, how will tech genius, Penelope Garica (Kirsten Vangsness) feel about Alvez replacing her best friend?

“The fun thing about that [Alvez’s] character is not that he’s a new [Derek], but what is Garcia going to think of the new guy?” “Criminal Minds” showrunner dished to TVLine, “There’s something real in the workplace environment where a friend leaves and you’re like, ‘I’ll never love anyone the way I loved that friend,’ so she has to warm up to him.”

Of course, warming up to him will not be easy. But given that he prove to be a valuable addition to the BAU, it shouldn’t take long for Garcia to become friends with him. However, fans of “Criminal Minds” should also watch the Season 12 premiere to see the reactions of other team members, including awkward genius Spencer Reid (Matthew Gray Gubler).

Season 12 will also be the last we see of Thomas Gibson’s Aaron “Hotch” Hotchner after Gibson was fired following an on-set altercation with “Criminal Minds” writer-producer Virgil Williams. Emily Prentiss (Paget Brewster) will most likely step in his shoes after Brewster was promoted to a series regular.

“Criminal Minds” returns with Season 12 on Wednesday, Sept. 28, at 9 p.m. EDT on CBS.

Criminal Minds It will be interesting to see how Penelope Garcia will react to Derek Morgan's replacement in “Criminal Minds” Season 12. Photo: CBS