The team committed 17 turnovers during their 98-79 defeat in their penultimate pre-season game.
The coach told reporters: "The guys that are getting an opportunity now are just basically letting it slip through their fingers.
"This is their chance to show that they are capable of holding down the fort or contributing in the rotation in some sort of way. Tonight is inexcusable and there's no way around it.
"Obviously we have a lot of work to do. It is the pre-season and we do have guys out, but like I said that's no excuse. I want to see who is going to fight and who is going to show some heart out on the floor and we didn't show that."
Denver play their final pre-season game against the Chicago Bulls tomorrow.