Simon returned from a lengthy injury at the turn of the year, while Michael stepped in for his debut in the win against Liverpool and both, Kasey feels, have added tenacity and pace in the central area.
"There is no question of what Simon and now Michael has done is given us the opportunity and ability to really close people down quicker than we probably did in the past," reasoned the goalkeeper.
"I think there has been a bit more demand from the coaching staff that we do that. There was a little bit of a deficiency for a while in that respect where we really let teams come at us. Now we're not, we're really closing teams down and making them earn what they get."
Kasey added that, while the pair do offer a quick-footed layer of protection, they did make a significant offensive contribution too.
"On the other hand, when you win balls in midfield and are able to counter from those positions, it is when you are extremely dangerous.
"When you are able to do that at pace, like Simon and Michael do, it makes a big difference."
Kasey Keller says the introduction of Michael Brown and return of Simon Davies has added a real snap to the midfield.