Manchester United are lagging behind their rivals in the transfer market this summer.

While the likes of Arsenal and Liverpool have both done good business, Jose Mourinho has been left frustrated with the club's activity.

The Red Devils have completed deals for Fred, Diogo Dalot and Lee Grant, but it's no secret that Mourinho wants more signings.

One area that the Portuguese manager wishes to strengthen is centre-back.

Eric Bailly, Chris Smalling, Marcos Rojo, Phil Jones and Victor Lindelof make up Man United's options in the middle of defence, but Mourinho seems unconvinced with each.

In an attempt to strengthen in that position, Mourinho has recently turned his attentions to Harry Maguire, but Leicester have so far been playing hard-ball in a potential move.

United are said to be prepared to pay in the region of £75m for the England star, but that does not seem to be enough in the eyes of Leicester.

So, with talks for Maguire hitting a roadblock, who will Mourinho turn to next?

Spanish publication Sport believe that the Portuguese manager has already identified the player he wants if he can't seal a deal for Maguire.

They report that Mourinho has asked Barcelona about Yerry Mina's asking price despite negotiating with Maguire at the same time.

Mina is currently undergoing negotiations with Everton, but Man United have asked him to wait before making a decision on his future.

Sport conclude by writing that they'll move quickly to tie up a deal worth around €40m for Mina if Maguire talks continue to stall.

That is smart from Mourinho. The former Chelsea boss is desperate to buy a centre-back before the season starts, and he is already making plans just in case a move for Maguire fails.

Mina would be a good alternative to Maguire, with the Barcelona defender proving his worth in Colombia's World Cup campaign.

Meanwhile, Mourinho has claimed that he would not pay to watch his side during their tour of the United States.

"The atmosphere is good but if I was them, I wouldn't come," Mourinho said.

"I wouldn't spend my money to see these teams. I was watching on television Chelsea against Inter and the people in Nice decided the beach was better. They didn't go to the game, the stadium was empty.

"I think the passion many Americans have for soccer deserves more. They deserve the best teams and invest to bring the best clubs to the US.

"But we, and some other clubs, were not able to give to the people the real quality football that can attract even more passion in this country."

Would you be happy with Mina if a move for Maguire fails? Have your say by leaving a comment below.