Muhammad Ibn Hasan At-Tusi writes:

فَـإِنْ قِـيـلَ فَـأَيْـنَ أَنْـتُـمْ عَـنِ الْـقِـرَاءَةِ بِـنَـصْـبِ الْأَرْجُـلِ وَعَـلَـيْـهَـا أَكْـثَـرُ الْـقُـرَّاءِ وَهِـيَ مُـوجِـبَـةٌ لِـلْـغَـسْـلِ وَلَا يُـحْـتَـمَـلُ سِـوَاهُ قُـلْـنَـا أَوَّلُ مَـا فِـي ذَلِـكَ أَنَّ الْـقِـرَاءَةَ بِـالْـجَـرِّ مُـجْـمَـعٌ عَـلَـيْـهَـا وَالْـقِـرَاءَةُ بِـالـنَّـصْـبِ مُـخْـتَـلَـفٌ فِـيـهَـا لِأَنَّـا نَـقُـولُ إِنَّ الْـقِـرَاءَةَ بِـالـنَّـصْـبِ غَـيْـرُ جَـائِـزَةٍ وَإِنَّـمَـا الْـقِـرَاءَةُ الْـمُـنَـزَّلَةُ هِـيَ الْـقِـرَاءَةُ بِـالْـجَـرِّ

,,Does one say: ﴾How are you removed from the reading with the accusative by Arjul (5:6), while the majority of the reciters advocate for it and it makes the washing (of the feet) necessary and nothing is possible except for that?﴿ So we say: ﴾The first to this consists in, that there is an agreement about the reading with preposition (Arjulikum), while the reading with accusative (Arjulakum) is disputed, because we say, that the reading with accusative (Arjulakum) is not allowed and the reading, that has been sent down, is only the reading with preposition (Arjulikum).﴿” [Tahdhib-ul-Ahkam, Volume 1, page 74]

Comment:

Asim is transmitted by Hafs. Therefore it is referred to as the reading of Hafs. At-Tusi documents further differences between Hafs and Imam Ali [Read here!]