The Republic of Ireland international, 24, trebled his Latics goal tally with a brace in the 3-1 win over Ipswich on Saturday which helped Rosler's side to their eighth straight victory in all competitions.
However, McClean has enjoyed an up-and-down first season at the DW Stadium, where he moved to after failing to make the grade at Sunderland despite a dazzling first few games in the north east.
Rosler admits that McClean, who joined the Black Cats from across the Irish Sea in 2011, is still a very raw prospect but is encouraged by the progress he is making under his tutelage.
"James is raw in many ways," the German said. "He's not come through the usual academy systems; he's come from Ireland. He has pure talent - there is a lot to work with.
"He is a player who can go all the way as long as he wants to go all the way. He has enormous potential to be even better and it's up to me and up to him to get more out of him and his potential.
"He's relatively young and he brings so much for a player in that position - he's quick, he can dribble, he's unpredictable and he has stamina, he can do it for 90 minutes. He can score goals, I think he should score more goals because he's very good in the air, he should attack more crosses."
Rosler is one of the more animated managers in the country and given McClean is usually stationed out on the left, there is nowhere to hide when he fails to heed instructions.
His boss admits he does work a lot with the Irish winger but is impressed with the progression he has made since Rosler's arrival in December.
Rosler continued: "I think he's heading in the right direction but there's a lot more to come from him.
"I think he sees that by himself. He's enjoying his football and he knows that we are working with him.
"Sometimes he gets annoyed about us working too much with him but he's coming on and he's in a good place at the moment.
"He's playing three, four starts out of five so that shows that he is a very important part of our team and we have to use him in the right way. I'm very happy to have him."