But despite a deal having almost been reached with the latter, Inter pulled the plug on the switch due to unrest among their fans.
However, that has not deterred United, who are reportedly planning an £18m swoop.
New Red Devils chief Louis van Gaal is known to be desperate to add some steel and dynamism to his engine room, with Guarin a genuine option.
Kevin Strrotman of Roma is considered to be his preferred target, but a bid would have to be shelved until January with the Dutchman currently out of action with a serious knee injury.
Guarin is available immediately, and is seen as a different option to any of United’s current midfield crop.
Despite the problems over the winter, Inter may be open to selling their man this time around as they set about a major overhaul following their recent takeover.