The Colombia international was close to sealing a switch to Juventus in January as part of a swap deal involving Bianconeri forward Mirko Vucinic, until club owner Erick Thohir pulled the plug on the transfer at the last minute.
Guarin - who has since extended his contract with the club despite being linked with Chelsea - has maintained he is not looking to leave the Nerazzurri, but his representative has made it clear that Mazzarri and the club will ultimately have the final say on his client's future at Appiano Gentile.
“Fredy is calm and always gives 100 per cent,” Marcelo Ferreyra told Calciomercato.com. “He wants to help Inter secure qualification for Europe.
“The fact the World Cup is approaching is also another reason for him to give his best.
“We will see what happens in the future. Inter and Walter Mazzarri will be the ones who decide.”
Inter are currently fifth in Serie A on 57 points, sitting five points clear of Torino, Lazio and Verona with three games left to play.