It will be a toss-up between Chief Boden (Eamonn Walker) and new firefighter Jimmy Borrelli (Steven R. McQueen) on who will leave Firehouse 51 in the upcoming season of "Chicago Fire."

In the last installment, Jimmy's brother died on Boden's watch while saving the injured people in a collapsing building. Many were spared, but he died. Jimmy blamed Boden for letting his brother undertake such a dangerous mission. Had the chief told the young firefighter to back off and think of his safety first, the accident would not have happened. When the pair eventually faced off, Jimmy told Boden exactly what he thought of him. Their skirmish is expected to continue in season 5, as Boden also has a lot to say to Jimmy.

According to executive producer Matt Olmstead, one of them will definitely leave the squad.

"The main battle going into next season is [between Jimmy and Boden], and one of them isn't going to be around [after it]," Olmstead told TV Line.

Chances are, it will be Jimmy who leaves. He may have stepped out of line when he started accusing Boden of negligence. The chief will definitely not take that lying down. He may ask for a transfer for the firefighter or he may do everything he can to get Jimmy out of Firehouse 51. It is also likely that Jimmy will leave on his own. Although his colleagues may understand his angsts over what happened to his brother, they may feel that his actions towards Boden were too much.

Meanwhile, the EP also talked about the predicament Severide (Taylor Kinney) would be in at the start of the new season. During last season's finale, he and Stella (Miranda Rae Mayo) were in bed together while her crazy ex-husband was waiting in the other room, holding a knife. According to Olmstead, there is going to be "knock-down, drag-out fight" that Severide will win. However, he and Stella will end up separating in the end.

NBC's "Chicago Fire" season 5 is scheduled to return to TV screens in the Fall.