Southampton have signed QPR defender Steven Caulker on a season-long loan.
Brentford midfielder Jonathan Douglas has been told his time at the club is over by new boss Marinus Dijkhuizen.
The England international, 23, joined Spurs in July 2009 from Sheffield United, and prior to establishing himself as the club's regular right-back he had loan spells back at United and also with QPR and Aston Villa.
Walker was voted the Professional Footballers Association Young Player of the Year for 2012 and has made 112 appearances for the north London club.
Walker made his Tottenham debut in a 2-0 win over Portsmouth in March 2010 but played just once in the following season before being sent to QPR then Villa.
Having proved his credentials on loan, he forced his way into the Tottenham first team and stayed there for the duration of the 2011/12 campaign.
He won supporters' hearts with a memorable winning goal against North London rivals Arsenal.
A month later he made his England debut at Wembley as a substitute against Spain and was handed his first start four days later in a 1-0 win over Sweden.Walker has won nine caps to date, the last of which came in the 4-1 victory over Montenegro, and is vying with Liverpool's Glen Johnson for a regular place.