The on-loan striker scored two goals and secured Burnley’s 3-1 win over Sunderland on Saturday.
Coyle said: “I’ve always had the greatest belief in David as a top-class player and that’s why we’ve brought him in.
“His two finishes were top class and he has got to use them as a stepping stone. I would love to have him permanently and as long as he’s happy I’m sure he can keep producing on the pitch.
“I speak to David on a daily basis but although he’s getting stronger I didn’t think he was quite ready for 90 minutes. Having said that I told him he still had a big role to play.”