Shaikhul Islaam Ibn Taymiyyah (rahimahullaah) said:
مَنْ ظَنَّ بِأبِي حَنِيفة أو غيره من أئمة المسلمين أنهم يتعمَّدون مخالفة حديث رسول الله ـــصلى الله عليه وسلم ـــ الصحيح بقياس أو لغيره فقد أخطأ عليهم ويتكلم إما بِظنٍّ أو هوى
”Whoever think that Abu Haneefah or other than him from the Imaams of the Muslims deliberately opposed an authentic Hadeeth of the Messenger (sallal-laahu-alayhi-wasallam) through Qiyaas or other than it, then indeed he (i.e. such a person) has spoken erroneously about them, and he has either spoken with speculation or desires.” [Quoted by Shaikh Muhammad Bin Haadi (may Allaah preserve him) in his explanation of Raf-ul Malaam. Audio Number 1: http://ar.miraath.net/book/8104]
Why is that the case? That is because these Imaams are all agreed (with certainty) that the Messenger (sallal-laahu-alayhi-wasallam) has to be followed.