McLean cost the Dons £300,000 during the winter transfer window when he moved from St Mirren, and has started the season on fire with domestic and European goals.
Gaffer McInnes said: “Kenny has fitted in brilliantly with us. It’s not always easy to make that transition from a club that is hugely dependent on him and battling relegation. There’s no doubt about his quality.
“It’s a big season for him. But it’s a big season for a lot of players.
“Kenny played a few positions at St Mirren and he was someone they looked to when looking for results. He took that on board brilliantly. Whenever we watched him we saw he always took responsibility. Even when things were not going well he was looking to impose himself and affect the game positively. He’s brought that attitude to our club and he backs himself to make things happen for us.
“Kenny’s job is to get amongst it. His general play has been terrific and we are more than happy with him.”