The Colombia international arrived at Appiano Gentile during the January transfer window but a calf problem has restricted him to just four Serie A appearances to date.Inter midfielder Fredy Guarin has admitted that he finally feels of \"use to the team\" after setting up Mauro Zarate for the decisive goal in Sunday\'s crucial 2-1 Serie A win over Cesena.The Colombia international joined the Nerazzurri on loan from Porto during the January transfer window but arrived at the Guiseppe Meazza carrying a nagging calf problem, meaning he was unable to make his debut until earlier this month.However, after three subsequent starts in Serie A, Guarin finally feels in a position to prove himself worthy of a permanent transfer.\"I\'m gradually starting to feel better and I\'m reaching my best level, and I can be of use to the team,\" the 25-year-old told Inter Channel.\"I\'m satisfied with my performance and that I was able to contribute to Zarate\'s goal and play for 90 minutes.\"I still feel a bit heavy on the pitch, especially towards the end of a match because in the Italian league you have to keep running until the very end of the match, and be careful never to lower your guard.\"I have to be able to be at my best for the full 90 minutes.\"Inter paid an initial €1.5 million to Porto to take Guarin on loan until the end of the season but they must hand over an additional €12m if they want to sign the player in the summer.