It was mentioned, as in the narration reported by Saheeh Muslim, the saying of the Prophet (صلى الله عليه وسلم): “Verily between man and between Shirk and Kufr (unbelief) is the abandonment of prayers.” 68 –Is the abandonment of worship considered Shirk?
Yes, it is Shirk in the general sense, because the person who abandons the prayers out of negligence has done so because he followed his lowly desires. Accordingly, he placed his desires foremost to the obedience of Allaah (سبحانه وتعالى ), and thus he became Mushrik from this perspective, just as Allaah has Said:
So anyone who follows his lowly desire, placing it foremost to the obedience of Allaah (سبحانه وتعالى ), then this deed of his is a type of Shirk even though the more specific meaning of Shirk does not comprise the aspect of relinquishment [i.e. of worship].
68 Reported by Muslim in his Saheeh, vol.1, no.146 and 147.