Through December and into January Guarin was repeatedly tipped for a move to Chelsea, only for Jose Mourinho and company to opt for Nemanja Matic instead.
And Juventus then pounced on the situation, agreeing a deal with their Milanese rivals to take the Colombian to Turin in exchange for Mirko Vucinic.
What followed was, in short, a convoluted mess. Inter cancelled the deal due to fan backlash, Guarin was barred from the squad - and David Moyes even played a role in reportedly turning down the opportunity to sign the midfielder.
All this, only for the Nerazzurri to reintegrate the beleaguered star and hand him a new contract last month.
The saga appears to have another chapter, however. Guarin has performed poorly since signing fresh terms - on Monday he committed an horrific error to deny Inter victory against Livorno.
And supporters are displeased. They’ve aimed their ire at the ex-Porto man, claiming he doesn’t deserve the Inter shirt after almost leaving in January.
This point inevitably reopens the case for Manchester United to make a bid.
Moyes was believed to have passed on Guarin, but if Inter are looking to offload him a cut-rate deal could be on the cards.
Badly needing dynamism in the centre of the park, the Scot could conceivably see the Colombian as a viable option at the right price.
Buying him at a reasonable figure would allow United to not put a huge dent in the transfer kitty with a single purchase. A raft of other quality players could also be brought in.
The idea may in turn be one to ponder for the Red Devils hierarchy. After spending big last summer for Marouane Fellaini to not live up to expectations, taking advantage of Guarin’s situation could contrastingly prove shrewd.
United will need guile in transfer dealings along with funds to return to the top. And if Inter do decide to let Guarin walk, the fallen champions could certainly do worse than signing him at a discount.