Inter, joint fifth in Serie A, host joint-bottom club Catania on Sunday (1400) after a turbulent week in which fan power appeared to be decisive in persuading club president Erick Thohir to call off the deal to exchange Guarin for Juventus forward Mirko Vucinic.
The Indonesian business tycoon abandoned the deal after fans wrote an open letter of protest and then gathered outside the club offices on Tuesday.
The decision angered Juventus, who said their bitter rivals had shown a lack of respect to both players and treated them unfairly.
Inter have won only one out of eight Serie A games since Thohir replaced Massimo Moratti in November and the new president has upset fans by warning them that the club are in a transitional period.
Thohir took over after the International Sports Capital consortium, owned by himself and two Indonesian partners, paid 75 million euros ($101.73 million) and took on all of Inter Milan's debt of about 180 million euros in exchange for a 70 percent stake.
Guarin's future remains uncertain, with media speculation now saying that he may move to an English Premier League club before the end of the transfer window.
The Colombian midfielder, who joined Inter two years ago, has been given two days' off following the collapse of the deal, according to Italian media.
Forward Diego Milito said there were no hard feelings against Guarin, who has reacted angrily to being substituted on a couple of occasions.
"We'll welcome him as we always have done because he's a great team-mate and he's always given so much," the Argentine striker told Inter's website.
"I'm not going to put myself in his shoes because it's between him and the club and we hope the issue can be resolved in the best way for everyone.
"All I can say is that Fredy needs to stay calm, whether he stays or goes...the rest of us are just thinking about Sunday's match."
"(I hope) that the fans support us on Sunday as they've always done, they've shown how close they are to us over the years, in the good times and bad.
"Unfortunately we haven't got results in 2014 but it's important to win on Sunday because that could be the turning point."
Defender Hugo Campagnaro said he hoped fans would save any jeers for the final whistle.
"The team is working very hard, but if we don't start winning again soon things will get tricky and morale will dip," he said.
"We know the fans want a win, we expect them to support us over the course of the 90 minutes, then if they want to boo and criticise us afterwards that's their prerogative because they're paying customers."
Inter have 32 points, 11 behind Napoli who are third in the Champions League playoff spot.
Inter's neighbours AC Milan are also in crisis mode after their shock Coppa Italia exit at home to Udinese on Wednesday in coach Clarence Seedorf's second match in charge.
Eleventh-placed Milan (25 points), who gave Seedorf a winning debut at home to Hellas Verona, visit Cagliari on Sunday (1400).
"When you play for a big club, you know the demands are high, but I told the lads to be as calm as possible," said the Dutchman, who replaced Massimiliano Allegri one week ago.
"I want hard work and effort to turn the situation around. I said one victory wouldn't change everything.
Leaders Juventus (55 points), knocked out of the cup by AS Roma on Tuesday, will be looking for their 13th league win on the trot when they visit Lazio on Saturday in what is threatening to become a one-horse race.
AS Roma, eight points behind in second place, are at Hellas Verona (Sunday, 1130) while Napoli, a further four points behind, host Chievo (Saturday 1700).
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- Sports & Recreation
- Erick Thohir
- Inter Milan