The Blues are understood to be long term admirers of the Bosnia international, who has been at Lazio since signing from Swiss side Young Boys in 2011.
The 28-year-old is something of a cult hero at Lazio, after scoring the only goal during last season’s Coppa Italia final clash with hated local rivals Roma.
However, sources in the Italian capital reckon he could seek a new challenge in the summer, after a campaign in which he has struggled to recapture his best form and fitness.
That could prompt Chelsea to reignite their interest in the midfielder, who they were linked with last summer.
However, Jose Mourinho could face a battle for his signature.
The £9million rated midfielder has admirers in both England and Germany, whilst reports in Italy suggest Juventus and Inter Milan are also monitoring his situation.
Jose Mourinho completed the signing of midfielder Nemanja Matic during the January transfer window, but could be in the market for further reinforcements, with John Obi Mikel being linked with a summer switch to Inter Milan.