Rumours in recent months have emerged suggesting that the North West outfit are keen on bringing the Portugal captain back to Old Trafford.
While Pallister has insisted that a transfer would not be straightforward for United, he believes that Ferguson is eager to re-sign the player who left the Premier League in 2009 for a record £80m.
"I know for sure that Sir Alex would love to have Ronaldo back at Old Trafford," Pallister told Goal.com.
"To be honest, I didn't think it would be likely, especially this summer, but I'm coming round to it now.
"A lot depends on whether [coach] Jose Mourinho stays at Real, but, if not, Ronaldo could be tempted into a return."