Southampton have completed the loan signing of QPR defender Steven Caulker, Press Association Sport understands.

Toby Alderweireld's decision to join Tottenham and a serious knee injury sustained by Florin Gardos has heightened the need to bring in defensive reinforcements at St Mary's.

Saints manager Ronald Koeman has spoken of his wish to acquire at least one more centre-back, as well as add some extra height in defence – a role it appears Caulker will now help fill.

Signed by QPR last summer, reports suggest Caulker moves with a view to an £8million permanent transfer – the amount QPR paid to bring him in from Cardiff last year.

The center-back will be looking to avoid a third straight relegation from the Premier League at Saints and to add to his sole England cap won three years ago.

Caulker said,

“I’m very pleased and very excited. This club has done fantastically well, especially over the last two years.

“To now join this club and to be a part of it for this year is something I’ve proud of.

“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.”