Southampton have signed QPR's England defender Steven Caulker on loan for the forthcoming season, the Premier League club confirmed on Wednesday.

Saints' manager Ronald Koeman made his move for Caulker to fill the void in his defence left by Toby Alderweireld's move to Tottenham and a serious knee injury sustained by Florin Gardos.

Caulker, who made his only England appearance in 2012, cost Southampton a "substantial undisclosed loan fee", but it is believed the deal is not with a view to a permanent transfer to St Mary's.

The 23-year-old centre-back only joined QPR last season from Cardiff and made 35 appearances as the west London club were relegated from the English top-flight.

"To now join this club and to be a part of it for this year is something I've proud of," Caulker told Southampton's website.

"As soon as I got the phone call to say a fee was agreed with Southampton, I was delighted to get the opportunity to come and play under a great manager.

"This club is an ambitious one, so to be part of this is a great opportunity - it's a chance for me to prove myself. I'm very excited for the season ahead."