The Colombia international appears to be on his way out of Inter and could continue his career in La Liga.
The Primera Division outfit is keen to add some fresh blood to the midfield before the transfer window closes on Monday and sees the 28-year-old Guarin as a valuable addition to the squad.
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Guarin was close to leaving Inter for Juventus last season, but the deal eventually fell through as both sides failed to reach an agreement.
The former Porto man then signed a new contract with Inter until June 2017, but the Giuseppe Meazza outfit remained keen to sell Guarin for the right price.
Guarin now seems destined to continue his career at Valencia after the Spaniards eventually agreed to the inclusion of an obligatory buy clause in the loan deal.
The only remaining talking point is the transfer fee, with Valencia initially hoping to lure Guarin away from his current club for €15 million, whereas Inter had set a €20 million asking price.
Both clubs are ready to move toward a fee somewhere in the middle, however, and it appears to be only a matter of hours before the deal is done.