Wallace Boden leaving during the season 12 finale of Chicago Fire was presented with a silver lining. Sure, the character would no longer be Firehouse 51 chief, but he would still be working as part of the Chicago Fire Department, and would be returning for the occasional cameo.
It sounded like a good solution at the time, and fans anticipated seeing Boden pop up to check in his old firehouse. That has not been the case thus far. The character has been MIA for the entirety of the season, and now that he's slated to return in the upcoming episode "Post Mortem," actor Eamonn Walker has had to answer some questions about his Chicago Fire future.
Walker is willing to "come back" for additional cameos

For starters, Walker made it clear he was thrilled to come back. "It was amazing to go back," he told Deadline. "It was amazing to put the uniform on. I’d missed everybody terribly, and the welcome that I got was second to none. I feel very privileged as an actor to have a cast, a crew, and a production office step up and welcome you home."
Despite being forthright with praise for his former co-stars and collaborators, Eamonn Walker kept his cards close to the chest when asked about Boden's future on the show. Sure, Boden is holding down the fort as Deputy Commissioner, but we're more interested in how he will interact with 51 in season 14 and beyond.
Walker did not reveal whether he has plans to return a second time, but he did assure fans that he would be more than willing if the producers contacted him. "The truth of the matter is, if they write it, I will always come back and do it if I can be here," he explained. "It’s a wonderful thing to be part of the Chicago Fire family. We support each other in so many ways that people can’t even possibly imagine, on and off the screen."
Boden is worried about favoring 51 over other firehouses

Evidently, there's an in-universe reason as to why Boden has been avoiding Firehouse 51 throughout most of the season. At least, that's how we're choosing to interpret Walker's comments about Boden and his perceived favoritism. "Now he’s got the whole Chicago Fire Department, so all of Chicago is under his wing," he noted. "He knows the reputation he received for having a favorite with Firehouse 51, and he can’t afford to have that as Deputy Commissioner."
We can understand and appreciate Boden's desire to keep his distance in an effort to maintain an impartiality. We're glad to have him back, and we will continue to hold out hope that he can return to 51 under less dire circumstances than the ones presented in "Post Mortem."
Chicago Fire returns to NBC on Wednesday, April 16.