Coyle has issued his players with a Hazard warning ahead of their European debut against Belgian side Zulte Waregem, where Thorgan is on-loan.
"This kid is going to have a huge career," Coyle said.
"If anyone is suggesting he is only at Chelsea to keep his brother company, they are being disrespectful to a talent who will get better and better. He will be a real threat."
For the big stories and the banter follow us on Twitter: @tribalfootball