Alli made the switch to Everton from Tottenham Hotspur in the January transfer window after suffering a steep decline in north London and becoming surplus to requirements.
Everton paid no fee initially for the midfielder and he has failed to command a spot in the team at the club under Lampard, with warming the bench a regularity for Alli.
Questions are increasingly being asked about why Everton signed Alli in January and Keys believes there is no way back for the player, who is in a decline which cannot be reversed, even by Lampard.
“I’m afraid he’s gone”, Keys wrote on his blog.
“Poch, Mourinho, Nuno and Conte have all failed to get a tune out of him.
“Lampard will as well. Dele will never be the same again.”
It has been suggested that Everton could cut their losses on Alli and look to offload him in the summer transfer window, but the Toffees are not currently planning to do so.
Whether Everton will rethink their stance if they are relegated remains to be seen.
