Chicago Fire technical director Frank Klopas says the rookie class is working well in training but distanced himself when asked who of the seven trialists would make the cut.

The Fire are in pre-season training in Arizona and the way the players are working hard for each other is pleasing to Klopas but says it is far too early to make decisions on who exactly will be added to the first team.

"Listen it's [early on] but so far everybody is working hard," Klopas told Chicago Fire Confidential.

"As every day goes by you get to see more and more and learn more and more about the players and their characteristics. It's still early to be making any [roster] decisions at the moment but the good thing is that the guys are all working hard and they have a fantastic attitude. That part has been great."

The rookies include draft picks Corben Bone, Kwame Watson-Siriboe, Drew Yates, Sean Johnson and Steven Kinney along with trialists Mark Blades and Jovan Bubonja.