Middendorp was let go on Monday just three days after Bielefeld lost 6-1 at Borussia Dortmund.
Sports director Reinhard Saftig said: "This is because of just one win from the last 11 matches. There were games when we thought it could not get any worse but it still did."
Copyright (c) PA Sport 2007, All Rights Reserved.
Do YOU want to write for GiveMeSport? Get started today by signing-up and submitting an article HERE: https://www.givemesport.com/writeforgms