Lukaku has been outstanding for the Baggies on-loan from Chelsea.
Ridgewell told Absolute Radio: "Yes he's a big strong big strong kid, I was going to say guy but he's more of a 19 year old kid, and no I think he's coming very well, obviously Longy started the season off doing really well and now Roms come in and put a few goals away, so there's a lot of competition up there and Roms only 19, he's stating his place very well.
"Yes he's difficult, very difficult, he's a big, strong, quick guy as it is and you want to try and put yourself up against them people every, day in and day out and him and Longy up front is a match for anyone I'm sure."
Ridgewell was talking to Ian Wright of Absolute Radio Rock n' Roll Football. Every Saturday from 5pm on 1215AM. For more, visit absoluteradio.co.uk/football.