Ronald Koeman will ask Everton to test Southampton鈥檚 resolve over Virgil van Dijk this summer.

The Blues boss wants to be reunited with the 25-year-old defender after he signed him for Southampton in 2015, but would be reluctant to match the Saints eye-watering £55m asking price.

Van Dijk, out injured for the rest of the season, is attracting interest from a host of clubs but Koeman is determined for Everton to be in the race for his signature.

However, Southampton are set to drive a hard bargain ahead of an expected bidding war for his services.

Chelsea and Manchester City have been credited with being interested in van Dijk who has emerged as one of the most sought-after centre-halves in the division.

Ronald Koeman speaks to Virgil van Dijk during a match between Stoke City and Southampton in March 2016

But Everton will hope the prospect of linking up with Koeman for a second time could help them in trying to convince van Dijk to choose Goodison.

The Dutch defender, signed by Koeman from Celtic in September 2015, also switched agents recently to move to the Wasserman Group - the same company that represents Koeman - and football insiders believe that will help the Blues鈥?cause.

However Southampton's sky-high valuation of the player remains an issue.

Michael Keane in action for England

Koeman is looking to bolster Everton鈥檚 backline this summer and as well as van Dijk being on his radar the Blues boss has Michael Keane and Harry Maguire on a list of potential transfer targets.

The Everton manager is willing to spend big on his defence this summer despite turning the Blues鈥?backline into one of the meanest in the league, though van Dijk's asking price could give them pause for thought.

Everton added Ashley Williams in a £12m deal from Swansea City in August whilst sanctioning the £50m sale of John Stones to Manchester City.