for the opening takbir while standing upright, before he begins to lower himself. If he were to lower himself while saying the takbir, he would have uttered the opening takbir while not standing; yet the opening takbir must be said while standing.
His statement, “and the opening takbir suffices for him”: the author did not discuss the recitation of al-Fatihah, because the well-known position of the school is that there is no recitation required of the follower. Thus, if he deliberately omits reciting al-Fatihah, his prayer is valid, as will come, if Allah wills.
According to the stronger view—that the follower must recite al-Fatihah in every rak'ah—al-Fatihah is waived for him here on the basis of both textual evidence and legal reasoning.
As for the evidence: al-Bukhari narrated the hadith of Abu Bakrah, may Allah be pleased with him, that he joined the Prophet, peace and blessings be upon him, while he was bowing, and the Prophet, peace and blessings be upon him, did not instruct him to make up that rak'ah. He came hastily, said the takbir before entering the row, and bowed. When the Prophet, peace and blessings be upon him, concluded the prayer, he asked, “Who did that?” Abu Bakrah replied, “I did.” He then said to him, “May Allah increase you in eagerness, but do not do it again.” (1)
This hadith has also been reported through a route other than al-Sahih, in which it states, “He wanted to catch the rak'ah.” (2) There is no doubt that he hurried only out of fear that he would miss the rak'ah. Had he not caught the rak'ah in this situation, the Prophet, peace and blessings be upon him, would have instructed him to make it up. Since he did not instruct him to do so, it is known that it was valid and that he counted it as one of his rak'ahs.