Summary

• Taylor Kinney is officially returning as Lieutenant Kelly Severide for the start of Chicago Fire season 12, but it is unclear how many episodes he will appear in.
• One theory for Severide's return is that his wife Stella finds him and convinces him to leave ATF behind and come back to Chicago.
• Another theory is that Severide's return is to give his relationship with Stella closure, potentially resulting in a divorce if Kinney plans on leaving the show.

It's official — Taylor Kinney is returning as Lieutenant Kelly Severide for (at least) the start of Chicago Fire season 12. Unfortunately, details surrounding the character's return to the NBC drama television series are minimal, so it is unclear whether he is appearing in one episode in the season, a handful of them, or all of them. So, since there is no information on how Severide shows back up at Firehouse 51, the theories for his return (and reunion with his wife and friends) have begun.

As viewers recall, Severide left Chicago toward the middle of Chicago Fire season 11 when he went to Alabama to participate in an Office of Fire Investigation (OFI) training camp. However, Joe Cruz learned that the camp had ended, and Severide still had not returned to Chicago. Cruz informed Stella Kidd, Severide's wife, of her husband's unknown whereabouts, and she later discovered that Severide had ed a Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) investigation. For whatever reason, he did not think this new information was important enough to tell Stella, but hopefully, fans will get more answers in the season, which still does not have a premiere date.

6 Stella Finds Severide & Convinces Him To Come Home

The most obvious reason for Severide's return in Chicago Fire season 12 is that Stella has found him (wherever his ATF investigation has taken him) and convinced him to leave ATF behind and come back to the Windy City with her. At the end of the season 11 finale, Stella took a few vacation days and set off to find her husband. The episode ended before she could reach Severide, of course, but the cliffhanger will undoubtedly be addressed in the season 12 premiere, whenever that will be.

If this theory turns out to be correct, there is hope for Stella and Severide's relationship. The one worry many had following his lack of communication with his wife toward the conclusion of the previous season was that it would lead to the end of the couple's marriage. So, if Stella can persuade Severide to return to Chicago and Firehouse 51 without any trouble, perhaps they will be okay. However, this is also dependent on Kinney remaining as a series regular in Chicago Fire season 12. If he is leaving the show and only returning to give his character closure, some other theories might be stronger.

5 The ATF Investigation Ends

One reasonable theory concerning Severide's return in Chicago Fire season 12 is that the ATF investigation concludes. Perhaps the lieutenant was always planning on traveling back to Chicago once the case was solved. So, even if Stella does find her husband, he could explain to her that he needs to finish what he started. In this case, Stella could return home and wait for Severide, and all would be well in their relationship. Of course, he would still need to explain why he didn't update Stella about his whereabouts and tell her that the OFI training camp had ended.

If Kinney plans on resuming his role as a series regular on the NBC drama series, perhaps the ATF investigation will lead to an exciting development for his character. Severide has always been interested in arson investigation, and his recent activities could influence him to pursue a career in the field. Hopefully, a promotion within the Chicago Fire Department would mean Severide still regularly appears on the television show. This next step in his career would make the most logical sense for Severide, though.

4 Stella & Severide Get A Divorce

It is quite possible that Severide's return to the Windy City is to give his relationship with Stella the closure that it deserves. Stella and Severide might decide that the lack of communication and distance in their marriage is too much for them to handle, resulting in a divorce (and maybe her moving on with Sam Carver). If Kinney is set on leaving Chicago Fire in the season and Miranda Rae Mayo, who plays Stella, is staying with the show, it would only make sense if their characters separated. However, this theory is contingent on Kinney's number of episodes in season 12 and if he decides to exit the NBC drama series.

3 Severide Returns For Mouch's Funeral

Chicago Fire season 11 ended on numerous cliffhangers, but perhaps the most significant (and frightening) one involved Randall "Mouch" McHolland. Mouch was hit with some shrapnel during a shoot-out in the finale and taken to the hospital, where the doctors performed surgery on him to remove the fragments. Once the firefighter came out of the operation, the of Firehouse 51 were told that he would be okay. Unfortunately, that soon proved to be false. When Christopher Herrmann visited Mouch in the hospital, Mouch started bleeding from his wound and began coding. The episode concluded before viewers could learn Mouch's fate.

If Mouch dies in the Chicago Fire season 12 premiere, it would only be right if Severide attended his funeral. He might still be in the middle of his top-secret ATF investigation, but Severide would drop everything to be there to his Firehouse 51 family during this troubling time. Of course, this is one of the more depressing theories, and hopefully, it does not come to fruition in the episodes.

2 Severide Comes Back To Celebrate Casey & Brett's Engagement

Another cliffhanger from the Chicago Fire season 11 finale revolved around an unexpected development in Sylvie Brett and Matt Casey's relationship. Jesse Spencer, who has played Casey since the pilot, left the show after season 10 but returned as a guest star a handful of times in season 11. After Firehouse 51 helped Casey stop a domestic terrorism group, the lieutenant decided that it was time to ask Brett to marry him, even though they had broken up at the beginning of the season, and he still had to go back to Oregon. The episode faded to black before Brett could answer Casey, and the season premiere will undoubtedly address this proposal.

If Brett agrees to marry Casey, Severide could return to Chicago to celebrate his best friend's engagement. Of course, the theory that would make the most sense is Brett telling Casey no since distance is still a significant issue in their relationship, which is not expected to change anytime soon. Plus, Spencer has not confirmed whether he is returning to Chicago Fire full-time. But if somehow Brett and Casey make it work, Severide would want to be there to celebrate with his friends.

1 Severide Only Briefly Returns To Quit & Say Goodbye

Since NBC has neither confirmed nor denied Kinney's series regular status for Chicago Fire season 12, the actor may only be returning to give his character closure. Severide has been a main character since the show premiered in 2012, and he deserves a proper sendoff. The only way that would be possible is if Kinney appeared in at least one episode to officially quit the Chicago Fire Department and say goodbye to his friends and colleagues. However, this theory might be a moot point if Kinney plans on staying with Chicago Fire.

All seasons of Chicago Fire are available to stream on Peacock.