After weeks of speculation Vidic confirmed on Friday morning that he is to end his eight-and-a-half-year spell at Old Trafford this summer.
The United captain is not the same player he was before he ruptured cruciate ligaments in December 2011, but the influence of the imposing 6ft 2in centre-back cannot be questioned.
"When I arrived at the club and saw Vida up close I thought 'wow'," Moyes said.
"He is a fantastic defender and a great warrior.
"They use the word quite loosely nowadays but if you think in terms of what that means, people like John Terry and Nemanja would come into that category.
"For years he has been a top central defender. He still is. He still plays a big part here but we felt it was the right thing to be open with it.
"His contract was coming to an end. We felt it was the right thing for him and we decided it was the right time to do it for the club.
"He will remain captain and continue to do it to the end of the season."
Last month Moyes belatedly began a major overhaul of his squad by smashing United's transfer record to sign Juan Mata from Chelsea.
The second chapter of that revamp came with the announcement that Vidic is to leave in June.
Rio Ferdinand and Patrice Evra, whose contracts also expire in the summer, could follow Vidic out of the door.
Having played such a key role for United over the best part of the last decade, whoever steps into Vidic's place has some big boots to fill.
That is not to say that Moyes will definitely spend big on a new centre-half in the close season, however.
In Jonny Evans, Phil Jones and Chris Smalling, Moyes already has players with a combined total of 384 United appearances to call upon, in addition to 49 international caps and six league titles.
"We are trying to nurture one along and bring them into the team," Moyes added.
"Phil Jones, Chris Smalling, Jonny Evans are already here. We will give them an opportunity to show what they are capable of."
Vidic returns from suspension to face Fulham on Sunday, but United will be without Evans because of a calf injury.
Jones is available after he recovered from the concussion he suffered against Stoke last weekend, but Marouane Fellaini has been ruled out for a week with a groin problem.