The Real Madrid goalkeeper believes that whilst his club trainer is a strong contender for the coach of the year award, the boss of the Spain team should claim the prize
The shortlist for the coach of the year award was released by Fifa on the November 29, with Pep Guardiola running alongside the other two candidates.
"I am coached by Mourinho every day and work with Vincente a lot every season so I appreciate how good they both are," Casillas told La Sexta.
"I think that Vincente has done more than enough to win it, but I also think that Mourinho is a good contender. Personally, I think it should be a competition between those two."
The Spain international went on to talk about whether he would ever be considered for the player of the year award, saying he felt that the importance of goalkeepers is underestimated.
"I do not lose sleep over it but it is true that goalkeepers are just as important in a team as any other player," he said.
"Some great goalkeepers have had amazing seasons and not come close to winning the award."