Chelsea reportedly sent scouts to watch Sergej Milinkovic-Savic as part of their preparation for a summer bid.
A transfer embargo kept activity down to a minimum at Stamford Bridge in pre-season and they are expected to push hard once it ends.
According to Daily Mail, the Blues reckon they can open bidding with an offer of £52million next year.
Lazio have remained belligerent in the face of Manchester United and Juventus interest but Chelsea hope their defence will soon fall.
Talk of an £86m valuation has persisted while Milinkovic-Savic continues to star for Lazio.
Club president Claudio Lotito rates the midfielder as his star man having scored 33 goals and assisted a further 23 since joining four years ago.
Reports in Italy claim rivals United have already secured a verbal agreement with Milinkovic-Savic over personal terms.
The Serbian international featured for the Aquile on Thursday night as they lost 2-1 to Celtic in full view of Chelsea, and no doubt plenty of other club’s scouts.
A profit of £133m was racked up by the West London side in pre-season thanks to the sale of Eden Hazard and their embargo ends next summer.
However Sun Sport revealed earlier in the week that Chelsea are mapping out a January spending spree amid growing confidence the Court of Arbitration for Sport will quash their ban on appeal.
In that event, a winger and striker to replace Willian and Olivier Giroud are the priorities – with targets including Callum Wilson and Timo Werner.