Tavares has spent most of his time as a Gunner on loan, rather than playing for the first team.
According to Alfredo Medulla, Chelsea have launched an investigation into Tavares.
They were discussing the sale of Cesare Casadei to Lazio when they inquired about Tavares.
The latter will be loaned to Lazio for the season, which can sign him permanently in the summer.
Chelsea may have asked Lazio if they would be willing to cancel their deal with Arsenal and let them buy Tavares instead.
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