The Spaniard joined the Gunners from Goddison Park in the summer of 2011 and has since become a key leader for Arsene Wenger which has not gone unnoticed by the Toffees boss.
"I'm not surprised (he has become such a leader). He is a very gifted footballer, he is a great lad to work with," Moyes told reporters ahead of Everton's home meeting with Arsenal on Wednesday night.
"I think the manager was probably surprised what he offers: he is a great professional, a really good footballer and I'll be delighted to see him back - just disappointed it is in an Arsenal jersey.
"I see Mikel now and when they are having a bit of a huddle he is the one who is the leader and I think they look to him, he has taken on a lot of the leadership qualities in that side."