The R's striker netted for the second successive game at Loftus Road on Saturday, having been axed earlier in the season.
Boss Warnock said: "He's a changed boy at the minute and all credit to him.
"He came to see me and asked me how he can get back in the team after I left him out. And I told him he had to show me on the training ground that he was hungry to come back in because his attitude wasn't good at the time.
"The penny's dropped. The last couple of weeks he's been fantastic. His eyes are bright, I know he's going to play well.
"And when he puts in the effort and works as well, we've got a good player."