Collison missed last summer's preseason due to a knee injury.
"Pre-season has been great for the boys so far," he confirmed to whufc.com. "It's been nice to get on a little run. It's four wins out of four and now we're in Germany where we should face some tougher tests and give us a picture of where we're at.
"It's great for me to be out there playing matches, even pre-season matches, because I love being out there playing football. I think it's the same for everyone. There is a really good atmosphere in the camp already and you can see it building and everyone is enjoying their work and already gearing towards Cardiff. It's great."