Jordi Alba is seen as one of the best leftbacks in the world, so it is no surprise that two of the best soccer clubs in the world are fighting for the Valencia player's signature.
Alba is a former Barcelona youth team player and the Catalan giants are desperate to bring him back to the Camp Nou as a replacement for Eric Abidal.
United are also keen as Sir Alex Ferguson sees Alba as a perfect long-term replacement for Patrice Evra.
Reports in Spain suggest Barcelona are the favorites with the Sport saying Valencia are resigned to losing Alba. Los Che Sporting director Braulio Vazquez said he expects Barcelona to make a bid.
"I suppose Barcelona want him because he's Catalan and plays on the left wing," Vasquez told Radio Galega. "We are obviously talking about an excellent player, and it's only normal that Barcelona are keen to sign him."
Another fullback linked with United is Costa Rican Bryan Oviedo with some reports suggesting United have already agreed a deal with FC Copenhagen. The defender has made no secret about his admiration for the Red Devils. "When the news came out, it was something I liked a lot and it gave me great motivation to carry on," Oviedo told Extra Deportes Canal 42.
"For now, I'm waiting. If Manchester tell me they want to buy me and there are other clubs interested, obviously the first choice would be Manchester.
"For me it is one of the best team in the world."
Michael Carrick had a decent season for United last season, but Ferguson is keen on strengthening that position with replacement Anderson failing to shine. Udinese hard-man Kwado Asamoah certainly fits the bill.
The Ghanaian midfielder's agent suggested his player could be on the move with Inter Milan and Juventus also interested in the defensive midfielder's signature. "I guess they want to sell, this is how I read the club's purposes," Asamoah's agent Caludio Vagheggi told Radio Sport.
"Discussions are ongoing, but I do not know who they are talking with. The players must wait until the parties agree. Even though the club intends to sell, their prices are high as they are valuable."
United are also tracking Mexican pair Hector Herrera and Marco Bueno. Liverpool were understood to be in pole position to bring the Pachuca duo to England, but the club's chairman Jesus Martinez Patino said United had also enquired. "It's not just Liverpool, Manchester United are also after Marco and Hector," said Patino to Raza Deportiva.
"However, we're of the thinking that they must first consolidate themselves in Mexico."