Salaamu Alaykum,
There is a statement of sahaba (Ibn Hazm) where he clearly said that, in Qur'aan there are 14 places of prostration.
Is it true that Imam Shafi has introduced or added one more "Sujood at-Tilaawah" in Surah-al-Hajj which made total 15 places of prostration in the Qur'aan.
Is this not innovation (Bid'ah)?
Jazaak ALLAHu Khair.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

The statement that the number of prostrations for the recitation of the Quran are 15 is the most preponderant opinion of the scholars . The evidence for this is that ‘Amr ibn Al-‘Aas said that the Prophet taught him 15 prostrations for the recitation of the Quran, among which are 3 in Al-Mufassal and two in Surah Al-Hajj [Quran, 22]. [Abu Daawood, Al-Haakim, Ibn Maajah and Al-Munthiri]

Therefore, this is the most preponderant opinion and not an innovated statement. In addition to this, if a scholar is of a particular opinion in a Fiqh issue, then his view should not be said to be an innovation even if it was not the preponderant opinion.

Besides, we do not know what you mean by your statement “there is a statement of Sahaba (Ibn Hazm)…”, if you mean that he (Ibn Hazm) was of the view that the number of prostrations for the recitation of the Quran is 14 based on statements of some Companions, then it is acceptable to say this, but if you mean that he is a Companion – and we do not think that you mean this – then Ibn Hazm is absolutely not a Companion and not a Taabi’i, and not even from the generation that followed the Taabi’is as he came a long time after that generation. 

Allaah Knows best.