Brazier will work alongside Leigh Harrison and will focus on UK growth offerings, with Harrison focusing on UK equity income mandates.
Brazier is expected to join Threadneedle in the first quarter of 2010 after quitting Schroders after 11 years.
Brazier is passing the management of his £543m Schroder UK equity fund and offshore offering to Ed Meier and Errol Francis.
He joined Schroders in 1998 and has been part of the UK equity team since 2002 having previously had responsibility for charity and private bank portfolios.
Brazier took on the management of the Schroder UK Equity fund from Christopher Metcalfe in April 2006, the fund is currently second quartile in the IMA UK all companies sector over three years to December 14, having fallen 5.3 per cent.