The Cardiff City man has been linked with a switch to San Siro for a number of weeks and pictures posted by Inter showed the 27-year-old training with the club's first team on Monday.
Rumours of a move to Italy gathered momentum after Medel excelled for Chile at the FIFA World Cup.
The combative midfielder started all four matches for Jorge Sampaoli's side in Brazil, as Chile reached the last 16 before being eliminated by the hosts.
Medel only joined Cardiff in August 2013 and was unable to prevent the Welsh side from suffering relegation from the Premier League in his first season.
Inter head coach Walter Mazzarri has been busy strengthening his squad during the close-season, as Inter attempt to improve on a fifth-place finish last term.
The likes of centre-back Nemanja Vidic, midfielder Yann M'Vila and striker Pablo Daniel Osvaldo have all been added to Inter's squad in the current transfer window.
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