Chicago Fire is looking to the future after Jesse Spencer's exit.

According to TV Line, the NBC procedural drama has cast Brett Dalton as Jason Pelham.

Pelham will appear on Chicago Fire Season 10 Episode 7 as the interim Lieutenant following Casey's departure.

The outlet states that the Agents of S.H.I.E.L.D. alum is attached to the cast on a recurring basis.

The official description of the episode does not mention Pelham.

"Gallo clashes with the new lieutenant temporarily filling in for Casey. Severide closes in on a dangerous and deadly arsonist," it reads.

Spencer officially exited Chicago Fire last month during the 200th episode, but his exit was strongly suggested ahead of the episode.

If you watch Chicago Fire online, you know Casey left Chicago to become the carer to the Darden boys.

Social sevices did not want them to be moved to another city, and thus, Casey gave up the life he had in Chicago to look after them.

Spencer's decision to exit was revealed shortly after the final episode aired.

“I realized I’ve been doing TV for a long time. I added it up, and I think this year is my 18th year of network television,” Spencer told reporters during a Zoom press conference, according to TV Line.

“I called [showrunner] Derek [Haas] and broke him the news, said I thought it was time to leave the show, and he agreed that we should at least get Casey to 200 episodes."

"It was a difficult decision because I’ve loved the show from the start, but there are other things that I would like to do in the future, and there’s some family that I need to take care of, and 18 years is a long time.”

“I was, of course, wanting to talk Jesse into staying and coming back,” Haas added.

“But I was very happy that he gave us five more episodes than just saying at the end of a season, which happens sometimes, too, like, ‘I’m out.’"

"That let us bring back a storyline from Season 1, which I know Jesse was excited about when we pitched it to him, to bring back the Darden boys and really tie in the pilot to Jesse’s leaving.”

Taylor Kinney, David Eigenberg, Eamonn Walker, Christian Stolte, and Joe Minoso are now the sole original series regulars left on the NBC firefighter drama.

Brett Dalton's other TV credits include Amry Wives, Deception, and Blue Bloods.

Catch new episodes Wednesday at 9 p.m. on NBC.

Paul Dailly was an Associate Editor for TV Fanatic.Follow him on X.