Manchester United are ready to test Tottenham Hotspur’s resolve over Eric Dier by making a renewed effort to sign him. They have had one bid turned down and with Spurs adamant the 23-year-old defensive midfielder is not for sale, it appeared José Mourinho had moved on to other targets, including Chelsea’s Nemanja Matic.

But with United poised to sign the Everton striker Romelu Lukaku from under Chelsea’s noses in a deal worth about £100m, it is unlikely they would sanction Matic’s move to Old Trafford. As a result United are considering a further push for Dier, who has always been Mourinho’s No1 target in the position, and they hope that a bid of about £50m may change Spurs’ thinking.

Dier is receptive to a move to United, largely because he lost his place as Tottenham’s first-choice defensive midfielder to Victor Wanyama last season, although Tottenham have insisted they are not prepared to entertain any bids for the player signed from Sporting in 2014.

Mauricio Pochettino came to realise he could not play them together in central midfield and it was the more versatile Dier who felt the squeeze, dropping back to play in defence. Pochettino had moved Dier out of defence and into defensive midfield for the 2015-16 season and watched him excel; Dier finished it as England’s starting defensive midfielder at the European Championship.

Pochettino prizes tactical flexibility in his players but Dier wants to nail down one position and he wants it to be defensive midfield. United would play him there and it has not been lost on Dier he would have the chance to make the role his own.

Tottenham are in a period of relative austerity because of the building of their new stadium. The initial quote for the project was £400m but it has rocketed to £800m and Pochettino is under no illusions he must make ends meet with his trading. He is open to the idea of cashing in on the £50m-rated right-back Kyle Walker, who is a target for Manchester City, but he would not want to lose Dier, whom he values enormously.

Pochettino has said he and the chairman, Daniel Levy, will decide on who is sold and the club will not lose anybody they do not want to sell. Dier is under contract until 2021 and he is not the type to rant and rave but United know money talks and they would also offer a huge salary increase.

Mourinho had looked set to close a deal for Matic last week only for talks to stall, which added to the United manager’s frustration.

However, they did sign the defender Victor Lindelof from Benfica for £31m in mid-June and the move for Lukaku has put a different complexion on United’s summer.

Lukaku is on holiday in Los Angeles with the United midfielder Paul Pogba. He is expected to complete the formalities of his move to United – including the medical – in the city and then join up with his new team-mates for the club’s five-match tour of the United States, which begins on Sunday.