White, 34, did not attend England's recent training camp in Portugal, although he has agreed to go on stand-by for the six-week tournament after formally ruling himself out of contesting a World Cup squad place.
Family reasons were also behind Northampton wing Ben Cohen's decision earlier this year to make himself unavailable for France.
Vickery said: "I can't speak for Julian, but I am disappointed myself he's not here because I think he is a great player.
"From a tight forward play perspective, there is no doubt Julian is one of the very best in world rugby. It's fact.
"But it is his decision. It is personal to him, and I think you have to respect that.
"I am surprised, personally. It is not something which was known to me. I didn't realise there were going to be issues.
"At the end of the day, maybe Julian has just made up his own mind what is really important to him. I can only speak hypothetically because I don't know the situation he is in."
White added: "It has been a very difficult decision for me to make, but having discussed it with my family and with (England head coach) Brian Ashton I have decided not to make myself available for selection for the World Cup this year.
"I have a young family, and I also have a farm to manage, and I feel I cannot commit to the length of time the squad will be away from home."
Vickery said: "It gives a huge opportunity for somebody else now.
"There is no doubt that Julian brings an awful lot of experience.
"He is a fantastic player to have around, but at the same time Matt Stevens is a huge asset to any squad, Andy Sheridan is getting back to fitness and Kevin Yates did a fantastic job on the summer tour."
White featured in all of England's Six Nations games last season, starting the final two Tests against France and Wales before being rested with a host of other players from the South Africa trip.
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