Manchester United are looking at the possibility of bringing in Ecuador international Frickson Erazo, while the Red Devils face competition from Chelsea for the signing of Hamburg star Heung-min Son.

United are expected to strengthen their defense in the summer, with the future of Rio Ferdinand undecided and Nemanja Vidic's injury problems not going away anytime soon.

While Argentine defender Ezequiel Garay of Benfica has been the name on everyone's lips when it comes to a defensive signing at the end of the season, United are also keeping their options open with several other names being lined up.

The 24-year-old Erazo, who plays for Ecuadorian club Barcelona SC, admitted he was aware of the interest from United, and wanted to prove to them that he is worth taking a shot at.

"It's true that there was initial contact, but it will not help if my performance drops," Erazo was quoted as saying by the Daily Mail. "I try not to think about this.

"It's really flattering that big European clubs are watching football in my country, but if you think about playing with Real Madrid or Manchester United you risk losing concentration."

Another player who is seriously being looked at is Hamburg forward Son, who has been in pretty good form for the Bundesliga side.

The likes of Tottenham and Liverpool have also been linked with the South Korean international in the past, but it looks like United now face stiff competition from Chelsea for the 20-year-old.

Son's agent Thies Bliemeister confirmed the interest in his client, and admitted a move in the summer could not be ruled out.

"A transfer in the next summer? He has signed a new contract with Hamburg SV extending it for one year, but there have been many offers for him as from Manchester United and Chelsea," Bkiemeister said.