Publications in Spain recently claimed that the Serie A club were considering a £50m pounce for the 28-year-old forward.
Costa has been linked with a move away from Stamford Bridge before, with reports in the summer claiming that he could return to former club Atletico Madrid.
However, the Spain international stayed put to play under new manager Antonio Conte, who has witnessed his striker score 10 goals so far this season.
Commenting on the recent speculation, Ausilio told Premium Sport: "To talk about this is absurd, we already have a very strong centre-forward. We will try to evaluate the positions we feel need strengthening."
Mauro Icardi has scored 12 goals in 14 league games so far this season.