Clarke has so far disappointed since his move from Wolves in January and has gone to John Sheridan's Oldham Athletic for a month in a bid to bring his fitness up to scratch.
MacLean has played second fiddle to Clarke a number of times this season and the move will give him more chance to show his worth as Wednesday's star striker.
The former Rangers man is out of contract in the summer and aims to play his way into deal negotiations by doing what he does best - scoring goals.
But before that, there's the small matter of the Yorkshire derby clash with Leeds and despite the Elland Road club struggling, MacLean knows that the game will not be as easy as everyone thinks.
He told Footymad: "It's a winnable game. It's a local derby though so a bit more is at stake, it'll be a tough game because we were down at the bottom last year and fighting for our lives so they will be doing the same.
"It's a hard place to go at the best of times and win there but this time it will be even harder but everyone will be looking forward to it and hopefully there will be a big crowd."