The Portuguese forward was due for a trial at Villa's Bodymoor Heath training ground but any hopes McLeish had of keeping the move quiet were extinguished when Djalo wrote about it on his Facebook account.
"We're just going to look at him on trial," said McLeish.
"Talk of signing him is very premature. I didn't really want it to be anybody's business, but I know the lad put it on Facebook himself, so what chance have you got?"
Djalo currently finds himself in limbo, after a transfer deadline day move from Sporting Lisbon to French side Nice was rejected by FIFA because the relevant paperwork was filed too late.
Asked about Djalo's strengths as a player, McLeish chose to keep his own counsel.
"I can't tell you anything about him just now," he told reporters. "I don't want to divulge anything. Look him up on Google."
Villa supporters found out about the deal after Djalo wrote "I go to Aston Villa" on his Facebook page.
Currently eighth in the English Premier League, Villa host Manchester United on Saturday.
Source: AFP
Source: AFP