However, Rovers made it clear they had no intention of parting with the man who scored 24 goals in his impressive debut season.
McCarthy said: "Chelsea were interested in me but that is in the past and I am a professional.
"My time in Porto under Jose was positive as we were always winning titles. That's impossible to forget.
"But now my head and my heart are only for Blackburn.
"My objective is to be the Premier League's top scorer this season and a goal at Stamford Bridge would be excellent."