Brewster is back in training after 13 months out with an ankle injury and has been with Klopp's squad in Marbella this week.
“When long-injured players start training, very often you see little changes in their movements," he told Liverpoolfc.com.
"At the beginning that was the case with him as well. But now it's good and now the steps will be much quicker, the longest part of the rehab is now over and that changed everything.
“The boy can go out on the pitch not only to smell it. Being around the boys and doing similar things - or even the same things - changed everything, especially for a young boy like Rhian.
“He grew as a person in that time and physically as well; he is a different stature when you look at him. Now he is a proper man. When he got injured, he was a boy. All will be good."