Meanwhile Liverpool are due to benefit from Jonjo Shelvey's sale from Swansea to Newcastle.
The Anfield club, who have signed Caulker from QPR on loan following his medical, inserted a sell-on clause for 30 per cent when they sold Shelvey to Swansea in 2013. That will equate to around £3.6million once his £12m move to St James' Park goes through.