But the 28-year-old maintains although the triumvirate will no longer be playing week in, week out together they will still be able to recreate their heroics on the international level.
"The challenge for me is to come in and prove myself to a lot of people who probably don't know who I am or what I have done," said Brown, who again impressed in Scotland's Test series over Argentina.
"As far as I am concerned I will be starting afresh down at Saracens, anything I have accomplished before does not matter. It is up to me to show my new teammates what I am about.
"It is going to be a struggle to leave Glasgow and Johnnie and John. I have said it before but we just love playing together.
"We have played 60 odd games as a unit and we have such a good understanding together.
"It has been fantastic playing alongside them and I have loved every game I have played with them but hopefully this will not be the end of the relationship and we can continue playing together for Scotland."
Brown had no shortage of suitors, notably from over the Channel, but it was Brendan Venter who won the race for his signature.
He will join the likes of England duo David Strettle, Richard Wigglesworth and Matt Stevens at Vicarage Road and despite the lure of bigger pay packets elsewhere Brown maintains he was sold on Venter's vision for the club.
"Saracens are really a club going places and I want to be part of that," added Brown.
"Brendan maintained in the past they had brought in some superstars but the club had no soul. Now though they are really trying to build a family club and they have had a fantastic season.
"I came down and met the coaches and I was instantly excited by their vision and where they want to take the club.
"They have got it right in terms of what they are doing on and off the field and I'm excited by the challenge ahead.
"They manage their players very well and help to take care of your career and your family which was an important consideration for me.
"They honestly could not do enough for me and that was gratefully received. Things like that can make your mind up and that did for me.
"After this tour with Scotland I will get a break and make sure I'm ready and raring to go at Saracens and the challenge of Guinness Premiership."