The Serie A giants have been tracking the Red Devils star for much of the summer, and were believed to be on the verge of tying up a season-long deal with Louis van Gaal having decided that the Belgian is no longer a needed player at Old Trafford.
A £4m fee with a view to a permanent move next year was mooted, but Fellaini’s injury worries – he was pictured leaving training yesterday on crutches – has scuppered the move as he faces a lengthy spell on the sidelines.
Napoli are still keen to get in a holding player, and will now look at Sandro.
The Brazilian was a target for the Naples outfit before they looked at Fellaini, and is also thought to be available for the right price.
Spurs are rumoured to want around £15m for the Brazilian, but Napoli may attempt to negotiate them down or look at an initial loan.